Auto trans comp failing?

[D Knight]

Where's Dave S when you need him? My auto has functioned flawlessly for years. Especially after all the solder joints were redone a few years ago. Now today, on the way home from a cruise in, it started in first and stayed there. I can place the selector into 2 and nothing happened. It still stayed in first. I made sure the connectors at the bulkhead and at the governor are clean and tight. The fluid is full and still smells like fresh fluid although I have not changed it. Then out of nowhere, it shifted into second, then back to first. I gave it a little more gas and it finally started to act normal. Any ideas? I am leaning toward the comp.

Has anyone bought the new digital unit, and do I need to send my old one back?




-D Knight-

[DMCMW Dave]

Where's Dave S when you need him? ..............Has anyone bought the new digital unit, and do I need to send my old one back?

-D Knight-

Right here actually. Still recovering from DCS.

One more test - get up to speed and remove the fuse (#13). If it immediately drops into third you have found the culprit.

We've sold dozens of the digital governors with zero failures.

You send yours in, we change the guts, test it, and send it back to you the same day we get it. I think all the DMCH shops work the same way. I don't like core exchanges because once in a while someone sends you a melted mass of wiring, and the next guy won't really like that.

[David T]

Sounds like the shift computer. Check the wiring, make sure it is not getting melted by the exhaust pipe. If the wiring is OK it is probably a bad solder joint.

[DeLorean03]

Dude, definitely get the DMCH digital governor. I have it on my car, and it is AWESOME. The shifts are much stronger and pronounced.

You won't regret it - get it.

[D Knight]

J, how long have you had it? I may remove it and check the solder joints again just to be sure. What is the warranty on the new one? If I do go the digital route, I'll be calling you, Dave.

Speaking of new unit, all that gets replaced in it are the boards? I assume they are a much better PCB than the original.


-D Knight-

[DeLorean03]

Had it since...Dec 2011!

To know I should not have to ever worry about this kind of stuff again from the governor = well worth it. The fact it's only $300 is awesome too - the analog one in 2003 - I believe, was $500.

[Jonathan]

Has anyone bought the new digital unit, and do I need to send my old one back?

I can vouch for the replacement shift computer. I have it on my car and it has worked great since the day it went in.


Right here actually. Still recovering from DCS.

One more test - get up to speed and remove the fuse (#13). If it immediately drops into third you have found the culprit.

We've sold dozens of the digital governors with zero failures.

You send yours in, we change the guts, test it, and send it back to you the same day we get it. I think all the DMCH shops work the same way. I don't like core exchanges because once in a while someone sends you a melted mass of wiring, and the next guy won't really like that.

I'm in complete agreement with each of Dave's points... unfortunately, the 4th one too. Endless apologies from me for that.

[D Knight]

28583isnt this suppossed to be sealed?


-D Knight-

[DMCMW Dave]

28583isnt this suppossed to be sealed?


-D Knight-

Typically a blob of RTV in it.

[D Knight]

Well the diag continues. Dave doesn't see anything wrong with the GC. What else can cause erratic shifting?


-D Knight-

[D Knight]

Also, when the selector in in first, how does the GC know to hold first?


-D Knight-

[DMCMW Dave]

Well the diag continues. Dave doesn't see anything wrong with the GC. What else can cause erratic shifting?

-D Knight-

How was it tested?

[David T]

How was it tested?

The problem can be a bad solenoid (very unlikely) or a bad wiring connection internal to the transmission from the plug connecting the shift computer. Dave S had a weird one where a blob of silicone was caught in one of the solenoids. Found it when he took the solenoids out. Shifting problems are most commonly caused by a malfunctioning shift computer so until you can rule it out conclusively it must remain the prime suspect. Shift hold is initiated by the valve body. The gearshift moves a valve spool inside the valve body configuring the hydraulics to only go up to the selected gear, ie, 1 only goes to one. D2 goes to 1 and then 2 and 3 allows full shifting range. It does not work on every car and there is no governor so it is up to the driver not to overspeed the motor. Pull the fuse to the shift computer and the transmission should start and stay in 3. If it won't you may have a problem in the valve body.

[Bitsyncmaster]

It looks like the switches (the two plunger switches) are bad. Very iratic resistance readings from megohm to Kohms. Only one normally closed pole seems normal. Looks like tranny fluid got inside. Should they be sealed? Can I open this switch unit up and clean them?

[David T]

It looks like the switches (the two plunger switches) are bad. Very iratic resistance readings from megohm to Kohms. Only one normally closed pole seems normal. Looks like tranny fluid got inside. Should they be sealed? Can I open this switch unit up and clean them?

If you are referring to 104003 solenoid assembly 4-5-3 they are not switches, they are coils. Depending on the meter you use you should see somewhere around 25 ohms on each one. This is not an accurate or definitive way to test coils. If you are talking about switch wired up to the shift computer, one switch is for the back-up lights and the other is for neutral/park start. Neither should have any effect on shifting.

[D Knight]

I didn't have any issues with it starting or the reverse lamps. Just shifting.


-D Knight-

[Bitsyncmaster]

If you are referring to 104003 solenoid assembly 4-5-3 they are not switches, they are coils. Depending on the meter you use you should see somewhere around 25 ohms on each one. This is not an accurate or definitive way to test coils. If you are talking about switch wired up to the shift computer, one switch is for the back-up lights and the other is for neutral/park start. Neither should have any effect on shifting.

Then this link info is wrong.

http://dmctalk.org/attachment.php?attachmentid=959&d=1307760816

[Elvis]

Where's Dave S when you need him? My auto has functioned flawlessly for years. Especially after all the solder joints were redone a few years ago. Now today, on the way home from a cruise in, it started in first and stayed there. I can place the selector into 2 and nothing happened. It still stayed in first. I made sure the connectors at the bulkhead and at the governor are clean and tight. The fluid is full and still smells like fresh fluid although I have not changed it. Then out of nowhere, it shifted into second, then back to first. I gave it a little more gas and it finally started to act normal. Any ideas? I am leaning toward the comp.

Has anyone bought the new digital unit, and do I need to send my old one back?

-D Knight-


The solder joints failed once - they will fail again as the PCB is single sided and has no thru hole connections.

In your case it may already have failed again.

Therefore I made my new PCBs double sided.
From the experience I have with our company from other PCBs, these will last MUCH longer than the single sided ones.

For the Europeans here - I offer to rebuilt the Governors with new PCBs, original circuit but much more reliable.
PN me if interested. Sooner or later all of you automatic owners will have the problem...

Elvis & 6548

[Bitsyncmaster]

Here is what I'm getting on the switches.

1-A = 0.3 ohms
Pressed 1-A = infinity

2-A = 0.4 ohms but you just touch the plunger sideways and it can jump from 200 ohms to 5 Mohms.
Pressed 2-A = infinity

1-B = infinity
Pressed 1-B = 0.4 ohms

2-B = infinity
Pressed 2-B is jumping around 100 ohms.

Note the the normally closed contacts open with very little movement on the plunger. The normally closed contacts have to pressed fully to the bottom to close the contacts. So if 2-A was bad the reverse lights would not come on full power. If 2-B was bad you may not force first or second gear only.

There is defiantly a problem with these switches. So can I open it up without damage? Maybe a soak in solvent would get the tranny fluid out.

[D Knight]

So the big Q is, if I buy the new digital unit from DMC, does it have a new multifunction switch with it?


-D Knight-

[DMCMW Dave]

So the big Q is, if I buy the new digital unit from DMC, does it have a new multifunction switch with it?
-D Knight-

No, you get the same one back unless it is bad, if that happens you get to find or buy a core. Failure in that switch is pretty rare. Nobody even tests for it (until now!). I have never see the neutral or reverse light function fail.

Interesting thing is that you may never notice the failure you seem to have. Worst case your manual pull-down won't work correctly, and how often do you use that? It would not show up in normal driving in "D".

A bigger worry would be losing the reverse lights or the ability to start the car in Park. But those switches seem to be working or you would have been complaining about that before now.

Dave B - have you tested the actual operation of the governor, i.e. its ability to control the solenoids as the speed goes up?

I don't know of a non-destructive way to open that switch up.

[Ron]

Also, when the selector in in first, how does the GC know to hold first?
When 1st is selected, one switch (S2) directly grounds one shift solenoid (Sol B), energizing it. This is called a demand (for "No 3rd"). [Same as selecting 2nd], AND, the other switch (S1) grounds a circuit controlling the other solenoid (Sol A). If this circuit thinks it is safe to do so, it will ground Sol A, energizing it. I.E. it will keep it in 1st and not let it shift up, but it will not do a down shift to 1st when there is high RPM & MPH). This is called a request (for "1st").
Refer to this Schematic-
http://dmctalk.org/attachment.php?attachmentid=957&d=1307760408

=======


It looks like the switches (the two plunger switches) are bad. Very iratic resistance readings from megohm to Kohms. Only one normally closed pole seems normal. Looks like tranny fluid got inside. Should they be sealed? Can I open this switch unit up and clean them?
FWIW- All of those switches have tested flaky for me...especially when removed, but, like Dave S, no problems with any so far....


Then this link info is wrong.
http://dmctalk.org/attachment.php?attachmentid=959&d=1307760816
He (it) is correct except selecting 1st is a Request, not a Demand ("Forced").

=======


If you are talking about switch wired up to the shift computer, one switch is for the back-up lights and the other is for neutral/park start. Neither should have any effect on shifting.
Actually they do. They are not simple on/off switches -- Each switch has four terminals and three positions.
Please check out the schematic (lower left corner) in first link above...

[D Knight]

When reinstalling, do the switched mount horizontally or vertically? It looks like horizontally but I don't remember how it came out.


-D Knight-

[Bitsyncmaster]

Soaking with solvent fixed the switch issues. Not sure if those switches get filled with ATF fluid. There is an O-ring on the switch housing but is that to keep dirt out or ATF in? The switch housing has two holes in the bottom so filling with solvent was just dump it in until it overflowed.

I just held the switch upright, filled with solvent (my flux remover solvent), pushed the plungers a few times, dumped the solvent and blew out with air. I did that three times.

I did not do an electrical test on the unit. I did have an electrical test back at work when I first fixed the unit with a bad solder joint and two blown caps (about 4 years ago). Owner now had intermittent operation so I was looking for bad solder joints on the circuit boards which I found none. If I was going to do a lot of work with these, I would set up a test circuit but since DMCH now has a proven change, I think rework would be rare.

[David T]

Soaking with solvent fixed the switch issues. Not sure if those switches get filled with ATF fluid. There is an O-ring on the switch housing but is that to keep dirt out or ATF in? The switch housing has two holes in the bottom so filling with solvent was just dump it in until it overflowed.

I just held the switch upright, filled with solvent (my flux remover solvent), pushed the plungers a few times, dumped the solvent and blew out with air. I did that three times.

I did not do an electrical test on the unit. I did have an electrical test back at work when I first fixed the unit with a bad solder joint and two blown caps (about 4 years ago). Owner now had intermittent operation so I was looking for bad solder joints on the circuit boards which I found none. If I was going to do a lot of work with these, I would set up a test circuit but since DMCH now has a proven change, I think rework would be rare.

I didn't realize the multi-function switches did the shift hold. I thought it was done hydraulically. I never opened up a multi-function switch but I did cut up a wiring harness and the large bulkhead connector. Could be why many cars won't shift hold. At least the back-up lights and neutral start never seem to fail! It will be interesting to see if your problem goes away now that you seem to have gotten your switch to work. If so, this may start showing up more as a failure as the cars get older and older.

[D Knight]

Dave S- are they supposed to allow fluid in them?


-D Knight-

[DMCMW Dave]

Dave S- are they supposed to allow fluid in them?


-D Knight-

They are immersed in fluid when installed. I've never cut one open to see what's inside.

[Bitsyncmaster]

They are immersed in fluid when installed. I've never cut one open to see what's inside.

That would be my guess also (I've never worked on the DeLorean AT). I would not think the ATF would cause problems unless dirt or if someone put in an additive (sealer) it may cause switch problems.

[D Knight]

If I run an ohm meter across the first two terminals on one of the output transistors, I get 3.52. The same with the other transistor. However if I go across the middle and last terminal I get open on the one and 8.8 ohms on the other transistor. Is one of them bad? Should I just replace them both and with what number?


-D Knight-

[Bitsyncmaster]

If I run an ohm meter across the first two terminals on one of the output transistors, I get 3.52. The same with the other transistor. However if I go across the middle and last terminal I get open on the one and 8.8 ohms on the other transistor. Is one of them bad? Should I just replace them both and with what number?


-D Knight-

You can not really test the transistors installed in the circuit. But it looks like the same circuit on each transistor. I pulled the transistors when I had it apart and they tested good. Make sure you use the same meter lead (red and black) on the same pin of each transistor when your testing (in circuit or removed from the circuit)

[D Knight]

Ok. Thanks Dave. I'm going to put it in now and see what happens.


-D Knight-

[DL4567]

Hi guys,

I have a question about my auto trans, and thought I'd post it in here since there's a good discussion already going. Not trying to steal the thread or anything, I can start a new one if you want.

Anyway, it seems that when cold, and you put the gear selector in "D," the transmission is in 2nd or 3rd gear (not 100% sure which) when you try to start moving. The car will go, but it's clearly struggling in too high of a gear. If I move the shifter down from "D" to 1, it will put it in 1st gear as intended, and will pull away from a stop like it's supposed to. But put it back in D and it seems to be in 3rd.

The whole issue goes away after just a few minutes of driving, or long enough that when I get to the first traffic light or stop sign, it starts in 1st with the gear selector in "D" no problem. But pulling away from the garage, out of the driveway, and away from the end of my street (while the car's still warming up) it seems to be more and more often exhibiting this problem.

ATF fluid level is fine, and I've had no trouble with it over the last 10 years of ownership. But this has gradually been getting worse over the past year or so. It used to be very occasional to almost every time I drive it now.

Is it as easy as getting the new digital governor? That would be great, but I don't want to necessarily spend the $300 if I don't have to.

[D Knight]

Sounds like it is a bad solder joint. Gets warm and makes connection. You can either try to rebuild the one you have or the better option would be to get MWs new digital unit. They've yet to have a failure. I'm going this route in the near future.


-D Knight-

[D Knight]

Looks like I still don't have 1st gear. Starts in second then shifts to third. Guess I'll be getting the new computer sooner than later


-D Knight-

[David T]

Looks like I still don't have 1st gear. Starts in second then shifts to third. Guess I'll be getting the new computer sooner than later


-D Knight-

Refer to chart on G:04:03, no 1st or 2nd in automatic. The listed causes include:
Harness, wiring, plugs, sockets, grounds 8
Governor/computer 16
Solenoid shift valves 18
Valve body 19

If you can shift hold then it is most likely an electrical problem. You should build a light box to see what is going on with the shift computer to see what it is actually commanding the valve body to do. Make sure the wiring is not burnt. Use table 5 on page G:04:01 to see when the solenoids are supposed to be energized. E1 is the one to watch but in Neutral, reverse, park, and 1st both should be energized. If you can't get 1st, the first thing to check is if E1 is getting power. Could be a blown output transistor and that can happen from burnt wiring. The typical failure mode for the shift computer is erratic shifting from 2nd to 3rd and 3rd to 2nd. Gets worse as things get hot. Caused by bad solder joints and the blown caps.

[DMCMW Dave]

Looks like I still don't have 1st gear. Starts in second then shifts to third. Guess I'll be getting the new computer sooner than later


-D Knight-

Don't drive it much like this or you'll be replacing the whole trans. This is really rough on the second gear clutch pack.

[D Knight]

I can put the lever into 1st and it's still in second. When I first reinstalled the CG I had all 3. Shifted fine for about 20 min. I come out this AM and now all I have is second and third.

What is E1?


-D Knight-

[DMCMW Dave]

I can put the lever into 1st and it's still in second. When I first reinstalled the CG I had all 3. Shifted fine for about 20 min. I come out this AM and now all I have is second and third.

What is E1?


-D Knight-

The first solenoid. Have you found any of the articles on test lights?

[D Knight]

Dave, you are a machine, on here even on a Holliday! Thanks, I'll park it. If I get the GC to you this coming week, can you repair it and test everything on it? Also, do you send the old boards back too?


-D Knight-

[D Knight]

I should just be able to put a dvom on the GC socket and check it that way right?


-D Knight-

[DMCMW Dave]

Dave, you are a machine, on here even on a Holliday! Thanks, I'll park it. If I get the GC to you this coming week, can you repair it and test everything on it? Also, do you send the old boards back too?


-D Knight-

Yes, we can do that. Typically we send it back out the same day.

We don't usually return the old boards, but nobody ever asks for them.

It's a lot easier to see with a couple of LEDs so you can watch both solenoid outputs.

[D Knight]

How often to the solenoids go bad?


-D Knight-

[DMCMW Dave]

How often to the solenoids go bad?


-D Knight-

Never


Sent from phone

[D Knight]

That's good to know. I'm going to pull it back out in the AM and get it out to MW. I'm looking forward to the reliability of the new one. The shift points and firmness are the same I assume?


-D Knight-

[NightFlyer]

The shift points and firmness are the same I assume?


-D Knight-

Hmm, how to describe this in terms that you'll understand....

OK, I got it - it will be similar to when the DJ shifts from ambient music to trance music at a rave :biggrin:

[D Knight]

I have it back out again and packed ready for Dave to upgrade it.


-D Knight-

[Elvis]

interesting comparison :-)

I'd love to compare a good original governor to the software unit.

Also - what has been done to make it more reliable over time, vibrations
and temperatur changes.
Since the light switch I am a bit sceptical :-P

(no wire to cut this time ? :-D )

[D Knight]

Dave S, when you rebuilt mine, did you check the operation of the old boards before the install of the digital ones?


-D Knight-

[D Knight]

I've never had it shift this solid. I can manually shift perfect now. Well worth the money to upgrade to digital. Thanks Dave!


-D Knight-

[Elvis]

Well that's the way the original works, too - if the solder joints on the PCBs are OK


Has anybody had the chance to compare too good units ?

[bfloyd]

Resurrecting an older thread instead of starting a new one. Reading through various threads here on the forums regarding the automatic transmission and erratic shifting, I'm inclined to believe my transmission governor may be on it's way out.

Putting the car in DRIVE, I can definitely tell I've got 1st gear. Getting up to about 20-25 miles an hour I can feel it shift into second. Third gear is a little trickier. Out on the highway, it seems to stay in second gear up to about 50-55 miles an hour then I can feel it shift into third, the RPMs drop, the engine quiets down, and it drives very well. However while cruising in the 50-60 mph range, if I let up on the gas just a little, the transmission seems it can't decide whether it wants to stay in 3rd, or shift back and forth between 2nd & 3rd. When I first got the car back together and finally on the road, I had mistakenly plugged in the wiring harness for the manual transmission, and it never shifted gears (only stayed in 3rd). I only drove it that way for about 10 - 15 miles... so hopefully I didn't do any damage to it in that short duration.

I spoke with "Steve" at DMCH last Friday, and he gave me some tips and troubleshooting pointers to do over the weekend - mainly check out the kick down cable, the full throttle microswitch, and of course pulling fuse #13 to see if it defaults to 3rd gear. I removed my throttle spools and linkage, cleaned and lubricated them good, and while it may not have corrected the transmission shifting thing, it did correct my high idle issue. I know from previously driving it with the governor disconnected it does in fact default to 3rd gear. The car only has a total of 8,900 miles on it, but it did sit untouched for 20 years before I bought it.

Does an automatic that can't decide whether it wants to stay in 2nd or 3rd and jumps back and forth in-between sound like a governor related issue? I'm more than willing to spend the money to repair or replace the governor if that's what it is, but at the same time don't really want to throw money on parts if they are not needed.

[Jonathan]

Does an automatic that can't decide whether it wants to stay in 2nd or 3rd and jumps back and forth in-between sound like a governor related issue?

Yes. From my own similar experience, this sounds like a failing shift computer governor.

[David T]

Yes. From my own similar experience, this sounds like a failing shift computer governor.

That is one of the symptoms of a malfunctioning shift computer. It can be repaired if you know how to use a soldering iron and get some replacement capacitors. Or you can have someone fix it for you or you can replace it. You have a few options BUT DO NOT continue to drive on it, you can cause internal damage to the transmission and that can get expensive. The main problems with the shift computer are bad solder joints and blown filter caps. Long periods of inactivity don't really hurt the transmission much except maybe the seals get a set and then start to leak when you start using it. Do all of the external On-Car checks as Steve suggested. Also inspect the wiring to the shift computer. If it gets too close to the hot exhaust pipes it burns the wires and and cause problems.

[Ron]

Also inspect the wiring to the shift computer. If it gets too close to the hot exhaust pipes it burns the wires and and cause problems.+1
... and since it's intermittent and the GC uses ground to switch the solenoids on and off, it could have simply rubbed through and be grounding the blue wire.

imho, it's probably well spent money on a ticking time bomb in any case though...

[axh174]

In addition to all of the above, I would also add that you should "reflow" all the solder joints on the computer boards (if you're handy with a soldering iron and choose to undertake replacing the aforementioned capacitors yourself). Bad/cracked solder joints can be related to erratic shifting because of the constant disconnect-reconnect of components in the circuit as the transmission warms up and as you bounce down the highway.

[bfloyd]

After two nights of fighting with the connector box (trying to find a place to squeeze it in-between the firewall and the engine), I enlisted the help of my wife with her dainty "girly-sized" hands, and she had it out within 10 minutes. Gotta love a woman who will crawl up in your engine bay at 10:30 at night and mess with your connector box! :eek7: Got the whole thing off the car, cleaned up and shipped off to Dave at DMCMW this morning for repair / replacement. New silicone pan gasket coming from Josh @ DPI, and hopefully everything will be back together by next weekend.

[Ron]

Sounds like you are on the right track!

P.S. You better take baby out to dinner!

========

Hey Smurf looking dude -- Where the heck you been hiding this time??

[axh174]

Hey Smurf looking dude -- Where the heck you been hiding this time??

[Off Topic]

Gargamel caught me.

Hey Ron! I don't get to work on the D as much as I used to, though I have by no means been without projects (got new fuel lines, fix hot start, chasing electrical demons, another coolant leak in the valley, etc.). Just really been super busy with work and other areas of life at the moment, which has kept me from frequenting DMCTalk as much as I would like. One of these days I'll get back into the swing of it.

[/Off Topic]

Good deal, bfloyd! Let us know how things go! When reinstalling, make sure you've got some zip-ties to keep the wiring harness clear of the cross-over pipe heat shield.

[Mark Hershey]

Yes. From my own similar experience, this sounds like a failing shift computer governor.

My experiences suggest the GC as well. I repaired my own years ago, and it still works fine, but the newer digital design Dave offers is well executed and now extensively proven in the field. You won't regret the upgrade 😀
// Mark

[cpistocco]

My experiences suggest the GC as well. I repaired my own years ago, and it still works fine, but the newer digital design Dave offers is well executed and now extensively proven in the field. You won't regret the upgrade ��
// Mark

Does anyone know EXACTLY which transmission governor components must be removed in order to replace the computer? I have gotten mixed reviews on whether or not the trans pan must be dropped. (I am planning to send the governor unit to dmch for a rebuild).
Thanks
Charlie

[cpistocco]

Does anyone know EXACTLY which transmission governor components must be removed in order to replace the computer? I have gotten mixed reviews on whether or not the trans pan must be dropped. (I am planning to send the governor unit to dmch for a rebuild).
Thanks
Charlie

[Ron]

You need to ask DMCH how much of it they want since there are several ways to do it.
If they don't want the multifunction switch, you don't have to remove the pan (the harness separates at the big black block on firewall with the brass fasteners).

[cpistocco]

You need to ask DMCH how much of it they want since there are several ways to do it.
If they don't want the multifunction switch, you don't have to remove the pan (the harness separates at the big black block on firewall with the brass fasteners).

Thanks Ron.... But honestly, I haven't been able to get a really straight answer on the subject (from them or anyone).

[Ron]

The whole thing:

38290

38288

[PJ Grady Inc.]

Thanks Ron.... But honestly, I haven't been able to get a really straight answer on the subject (from them or anyone).

You didn't ask me. I'd give you an honest answer. Then again you didn't answer my PM either!
Rob

[cpistocco]

You didn't ask me. I'd give you an honest answer. Then again you didn't answer my PM either!
Rob

Hello Mr. Grady
You're right... I did not ask you (but I try not to bother you all the time)! I know you are busy. Also, I did not realize that you sent me a pm. I will check it out now.
Thanks
-Charlie

[cpistocco]

The whole thing:

38290

38288


Thank You, Ron.
Much appreciated....
-Charlie

[DMCMW Dave]

It's generally easier to send in the whole thing as that allows us to inspect or repair burnt solenoid wiring, and when doing the governor it's not a bad idea to clean the pan, refresh the O-rings, and change the filter anyway. So the correct answer is "it depends".

BTW this answer applies to DMCMW only, you may get different answers from different vendors, even within the DMC network. As Rob mentioned, the "standard" is to send it in with all the cables still attached. this means you remove the pan.

We do often get them with the solenoid wiring removed, i.e. the pan was not dropped. You need to drain the ATF in either case. Make good notes about how to connect it back up, and go easy on the brass screws as they are very easy to break off. It is usually done this way if the trans service is recent and/or the owner really just does not want to drop the pan at this time.

We can do a function test with or without that cable attached, but please leave the 3 brass screws in place as that is where the tester gets attached.

[cpistocco]

It's generally easier to send in the whole thing as that allows us to inspect or repair burnt solenoid wiring, and when doing the governor it's not a bad idea to clean the pan, refresh the O-rings, and change the filter anyway. So the correct answer is "it depends".

BTW this answer applies to DMCMW only, you may get different answers from different vendors, even within the DMC network. As Rob mentioned, the "standard" is to send it in with all the cables still attached. this means you remove the pan.

We do often get them with the solenoid wiring removed, i.e. the pan was not dropped. You need to drain the ATF in either case. Make good notes about how to connect it back up, and go easy on the brass screws as they are very easy to break off. It is usually done this way if the trans service is recent and/or the owner really just does not want to drop the pan at this time.

We can do a function test with or without that cable attached, but please leave the 3 brass screws in place as that is where the tester gets attached.

Thank You Dave.
That was quite helpful. I have a new filter...and am ordering a trans pan gasket...BUT I am not sure what to do with O-rings that you mentioned.
Thanks again
Charlie

[David T]

Actually the best approach is to remove the pan and the solenoids. Dave S can tell you about the time he had a problem and when he removed one of the solenoids and found a blob of silicone blocking the port preventing it from shifting. The only way you are going to find something unusual like that is to actually go looking for it. That means getting your hands dirty and taking things apart.
These cars have had many hands on them over the years and some of the work usually was not done properly. If your automatic transmission never worked properly you cannot take anything for granted and should inspect everything. That includes going over every inch of the external wiring harness for any heat damage. Very commonly, if the cables were not secured away from the hot exhaust pipes, the wires get melted and that damages the shift computer.

[DMCMW Dave]

Thank You Dave.
That was quite helpful. I have a new filter...and am ordering a trans pan gasket...BUT I am not sure what to do with O-rings that you mentioned.
Thanks again
Charlie

There is one o-ring on each if the plastic cable ends that stick into the trans (i.e. the solenoid connector and the reverse/safety switch). Replace them. They are shown in the parts manual but on two separate pages. We add them automatically, not sure what everyone else does.

103698 and 103732

[cpistocco]

Actually the best approach is to remove the pan and the solenoids. Dave S can tell you about the time he had a problem and when he removed one of the solenoids and found a blob of silicone blocking the port preventing it from shifting. The only way you are going to find something unusual like that is to actually go looking for it. That means getting your hands dirty and taking things apart.
These cars have had many hands on them over the years and some of the work usually was not done properly. If your automatic transmission never worked properly you cannot take anything for granted and should inspect everything. That includes going over every inch of the external wiring harness for any heat damage. Very commonly, if the cables were not secured away from the hot exhaust pipes, the wires get melted and that damages the shift computer.

Point taken.....
I can tell you this much: When car is cold, it shifts poorly. Once it warms up....shifts like new. Does this mean anything to anyone? Either way, I will pull out ALL components.
Thanks
Charlie

[Ron]

Point taken.....
I can tell you this much: When car is cold, it shifts poorly. Once it warms up....shifts like new. Does this mean anything to anyone? It may mean if you change out the filter while you are in there, and the problem goes away, you'll never know :deviltail:

[Jonathan]

The "bad while cold and good while warm" description sounds more to me like a fluid related problem than it does a shift computer governor failure.

Like Ron said, it could be solved with the new filter (assuming you have one of Michael's filters for this?) and putting fresh fluid in there while you do so.

Bad shift computers generally end up seeing the car do strange things in certain gears, like revving high before going from 1st to 2nd, or feeling like it is staying in 3rd the whole time. Low fluid will get your transmission to slip and a plugged or clogged filter will rob you of power if bad enough.

Shift computers aren't cheap to take out and repair, more expensive than trying to replace the filter and fluid anyway. If it isn't the fluid and filter though that is the problem, you'll end up doing another round of new fluid ($20 worth perhaps?) and another pan gasket depending on what you use. If you have the time, I'd suggest doing fluid plus filter first and the shift computer repair later.

How would you describe your problems with the trans shifting? What does "bad while cold" mean in your case?

[DMCMW Dave]

The "bad while cold and good while warm" description sounds more to me like a fluid related problem than it does a shift computer governor failure.

?

It's actually a pretty common failure mode with the governors. Electronics.

[Ron]

Dave,
On level ground, going say 50 MPH, if you let off the accelerator completely, and shift to 1st, what speed will the trans actually go into first.
AND, what is the highest speed you would expect to get a downshift to 1st when flooring it on the way down instead?
Just off the top of your head for OEM and the "more aggressive" DMC replacement, please.

thx

[DMCMW Dave]

Dave,
On level ground, going say 50 MPH, if you let off the accelerator completely, and shift to 1st, what speed will the trans actually go into first.
AND, what is the highest speed you would expect to get a downshift to 1st when flooring it on the way down instead?
Just off the top of your head for OEM and the "more aggressive" DMC replacement, please.

thx

1 - Never tried it. I don't like to blow up transmissions. My personal car is a manual and I don't beat on customer cars.
2 - Maybe 35? Not really sure here either, it's not a test I try often enough to recall. Having driven the new vs. the old governors, I can't say that there is a huge difference between an OEM governor working properly (BIG caveat there) and the new one.

If anything the new one will hold lower gears slightly longer on acceleration. The new ones are much more consistent. You don't realize now much variation there is in the OEM governors until you drive different cars back to back. My suspicion is that people who say the replacement is more aggressive were dealing with an OEM version that had been on the way out for a long time.

The OEM governor is analog electronics, so as components age its behavior can change.

[Ron]

1 - Never tried it. I don't like to blow up transmissions. My personal car is a manual and I don't beat on customer cars.
...

Thanks!

BTW- Shifting to 1st is a "request", not a "demand" -- It won't hurt it...:tongue2:

[cpistocco]

Thanks!

BTW- Shifting to 1st is a "request", not a "demand" -- It won't hurt it...:tongue2:

My basic "cold" condition is this- Not shifting from 1st to second (revving too high). Or not being able to "decide" which gear it wants to be in at certain speeds. After warm up- no problems. BTW I purchased a new filter last month. great product. Hope he makes more.
-Charlie

[PJ Grady Inc.]

It may mean if you change out the filter while you are in there, and the problem goes away, you'll never know :deviltail:

Sounds like a bad computer to me as the problems are most often temp sensitive and usually appear when cold first. A filter can't fix this problem.
Rob

[Ron]

My basic "cold" condition is this- Not shifting from 1st to second (revving too high). Or not being able to "decide" which gear it wants to be in at certain speeds. After warm up- no problems. BTW I purchased a new filter last month. great product. Hope he makes more.
-CharlieWell nix deciding between the GC and filter.

Are you comfortable with a small soldering iron in tight places?


Sounds like a bad computer to me as the problems are most often temp sensitive and usually appear when cold first. A filter can't fix this problem.
RobAgreed.

Yeah, my guess was a GC too, even before posting all of the symptoms. Neither of those symptoms (alone) would indicate a filter, on a D (more likely with not taking gear initially, the high was due to slipping v/s up-shifting....you know).

===============================

I'd make bets for bad solder joints on the GC now.

[David T]

Sounds like a bad computer to me as the problems are most often temp sensitive and usually appear when cold first. A filter can't fix this problem.
Rob

While a faulty shift computer will be temperature sensitive, other things that could be wrong can also be affected by temperature. For example if the fluid is low it will shift badly but as the fluid warms up and expands (you get a higher level) the shifts get better. Not all ills that are temperature sensitive can be attributed to the shift computer. In fact, a temperature sensitive shift computer often works fine cold and starts acting up as things get hot. I have also seen where the wiring gets melted to the exhaust pipes and the problems begin as the wires are remelted on the hot pipes. When you have problems with your automatic transmission the first thing you should do is all of the external On-Car checks as per the Workshop Manual, including checking fluid levels and examining the shift computer wiring.

[PJ Grady Inc.]

While a faulty shift computer will be temperature sensitive, other things that could be wrong can also be affected by temperature. For example if the fluid is low it will shift badly but as the fluid warms up and expands (you get a higher level) the shifts get better. Not all ills that are temperature sensitive can be attributed to the shift computer. In fact, a temperature sensitive shift computer often works fine cold and starts acting up as things get hot. I have also seen where the wiring gets melted to the exhaust pipes and the problems begin as the wires are remelted on the hot pipes. When you have problems with your automatic transmission the first thing you should do is all of the external On-Car checks as per the Workshop Manual, including checking fluid levels and examining the shift computer wiring.

IMHO you are just making the situation more confusing David by seeding doubt. In my experience the vast majority of computer failures begin with a cold transmission shift problem. While it can begin when hot it is rare. We've replaced hundreds of computers and I am rather familiar with any/all symptoms. I'm 95% sure it's the computer. I'll await your reply as I've never gotten the last word in with you. Please don't get this owner any more confused than he already is ;)
Rob

[cpistocco]

Hi Guys
I am most grateful to all of you.....
I will let Rob and Dave in on the solution as soon as it is resolved... There may be a small prize involved for the winner. :)
ps
ALL of the fluids in this vehicle are at proper levels. :)

[PJ Grady Inc.]

Hi Guys
I am most grateful to all of you.....
I will let Rob and Dave in on the solution as soon as it is resolved... There may be a small prize involved for the winner. :)
ps
ALL of the fluids in this vehicle are at proper levels. :)

Wow Dave held his tongue but got back at me anyway. Yesterday he and an accomplice entered my basement and carried away my BTTF pinball machine. I hate when that happens!
Rob

[David T]

Wow Dave held his tongue but got back at me anyway. Yesterday he and an accomplice entered my basement and carried away my BTTF pinball machine. I hate when that happens!
Rob

On the bright side, it went to a good home where it will be played with a lot and enjoyed by many. When the new owner wants to be known I am sure he will invite us over to see it and his collection. Right now he is busy trying to wake up a Delorean that has been asleep for almost 20 years! Needs all of the usual stuff but at least it was kept indoors and is virtually complete.

[PJ Grady Inc.]

On the bright side, it went to a good home where it will be played with a lot and enjoyed by many. When the new owner wants to be known I am sure he will invite us over to see it and his collection. Right now he is busy trying to wake up a Delorean that has been asleep for almost 20 years! Needs all of the usual stuff but at least it was kept indoors and is virtually complete.

True....never had much time to play with my machine anyway!

[cpistocco]

True....never had much time to play with my machine anyway!

Funny!! :)