Changing the transmission fluid (once more)

[DrWin]

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So this happened today while I was refilling the transmission: The dipstick broke. :(
That's pretty annoying, but easy to remedy. I ordered a new pan gasket and a new dipstick from Ed.

But that only scratches the surface of the many questions I have about the mysteries of the automatic transmission (fluid):
I spent last night crusing the internet for answers and found all sorts of answers. (?)

I read that I need to add 2.5L transmission fluid when doing the change, I also read 4.5L, I also read 4.5 quarts (4.1L). When reading about the automatic transmision I read that a full (assume US) gallon (3.8L) stays in the final drive, why I'd suspect I'd need to put 2.2L back in, as the total capacity is 6 L. I'm confused. :)

I also read in the manual that it takes ATF Dextron II, which I've been using, but internet ressources says ATF Dextron III. Which is it, and why?

I was pointed to the Renault 4141 manual for the transmission and read about a temp probe that should go into the transmission to measure the temp, so it gets tested at the right temperature instead of "after a few minutes of idling". I can't find a place that sells the mentioned temp. probe.

Also - and perhaps most basic and important - why the hell am I having such a hard time reading the dipstick? I think it's very difficult to get consistent readings when checking the automatic transmission fluid level. Am I the only one having this problem? To me it looks like the dipstick will come out with light coating no matter the fluid level and when I put fluid into the transmission I get very inconsistent readings from test to test. Is the dipstick orientation specific? Where should the fluid stand "after a few minutes of idling"?

So many questions, so little understanding. If anyone would help me wrap my head around this, while I wait for my package from Ed, I'd sure appreciate it. (Also I have a sneaking suspicion that my transmission would appreciate I got some help.)


How did the magnet in the pan break?
How did the dipstick break?
Where do I get a renault temp guage for the transmission fluid?
What is the actual deal with the dipstick, why is it so hard to read?
Should I change from ATF II to ATF III?
If so, will that make the dipstick easier to read?

[Michael]

Final drive takes gear oil, not ATF. The reason you don't replace the full amount is the fluid in the cooler lines and converter stays in place as well as say 1/4 qt in all the tight spots and passages.

The neodymium magnet is very brittle, you can't drop it in the pan. If it smacks a surface hard, it will break.

I don't know anything about a temp probe, but you have to check the fluid at a proper time. Fluid has to be at least warm. Engine running, car in park, level ground. New fluid is hard to see but if you have just added fluid through the dipstick tube, you can't immediately check the level as all that fluid in the tube has to work it's way into the pan and settle.

Manual is outdated. Just get Dextron III and be done with that. I'm not even sure if Dextron III is avaliable anymore...seems like the last time I checked another "one size fits all" fluid was on the shelf, Dextron VI? IDK, but just tell the 17yr associate that's never changed a oil filter that you are working on a DeLorean Renault 4141 and he will be sure to help you out.

[DrWin]

Manual is outdated. Just get Dextron III and be done with that. I'm not even sure if Dextron III is avaliable anymore...seems like the last time I checked another "one size fits all" fluid was on the shelf, Dextron VI? IDK, but just tell the 17yr associate that's never changed a oil filter that you are working on a DeLorean Renault 4141 and he will be sure to help you out.

Yeah... :)

[DrWin]

Final drive takes gear oil, not ATF. The reason you don't replace the full amount is the fluid in the cooler lines and converter stays in place as well as say 1/4 qt in all the tight spots and passages.
Right, got it. I wrote that wrong. I have gear oil in the final drive, not ATF.


The neodymium magnet is very brittle, you can't drop it in the pan. If it smacks a surface hard, it will break.
Roger, that is propably what happened, I checked that I couldn't hit it with the dipstick, so it isn't that either.


I don't know anything about a temp probe, but you have to check the fluid at a proper time. Fluid has to be at least warm. Engine running, car in park, level ground. New fluid is hard to see but if you have just added fluid through the dipstick tube, you can't immediately check the level as all that fluid in the tube has to work it's way into the pan and settle.
This! This is my problem. How warm? How long to settle?


Manual is outdated. Just get Dextron III and be done with that. I'm not even sure if Dextron III is avaliable anymore...seems like the last time I checked another "one size fits all" fluid was on the shelf, Dextron VI?
Roger. I'll look for some Dextron III when I get my spare parts.

Thanks again for the input.:)
You have an automatic -would you mind sharing how you do this refilling the transmission oil manouvre?

[Michael]

If you drain 2.5qts out, put 2.5 back in. The "cold" portion of the dipstick gets you close. Start it up and let the fluid come up to temp and check the level. After a short drive just to make sure the fluid is hot, I always check it again. It takes a few minutes for all the fluid to leave the tube so just clean the garage up while you wait.

It's not a bad idea to check your fluid level after a drive every so often, once a month, few times a year depending on how many miles you drive. Also keep a watch on the final drive level. Many leak into the trans and as a result, many final drives are very low.

[David T]

It is impossible to drain all of the fluid out unless you take it all apart. Much of it stays in the torque converter. All Dexron is backwards compatible, you probably won't find II anywhere anyway. It can be difficult to read the dipstick especially if it is overfilled. Follow the procedure in the manual. Don't forget the final drive must be checked separately and uses a different fluid. You cannot take the Renault manual directly and use it for the Delorean. Forget about the temp probe. Do not put back the same amount of fluid you took out, it may have been overfilled. Fill to mid-way between the add and full marks when hot on level ground. If you took the pan off you should either clean the old filter or replace it. Because you can't get all of the old fluid out you *could* go to a service station that has a power flush and have them flush the transmission. They hook up a machine that flushes the old fluid out and fills the transmission with fresh fluid. Best you can do without taking the transmission out and apart. Not really necessary unless your old fluid is very dark and burnt.

[Michael]

Blah blah blah...repeating previous postsverbatim...blah blah blah.....Because you can't get all of the old fluid out you *could* go to a service station that has a power flush and have them flush the transmission. They hook up a machine that flushes the old fluid out and fills the transmission with fresh fluid. Best you can do without taking the transmission out and apart. Not really necessary unless your old fluid is very dark and burnt.

Do NOT ever take your DeLorean for a "power flush". This is a BS service designed to make money off of soccer moms and Gurus. It could seriously damage your transmission and best case do more harm than good. It's utterly ridiculous to even mention doing this.

If you are determined to change all your fluid, my solution (and one that I have been following for the past 3 or 4 years), just drain your fluid every other oil change. The plug is right there, it's no problem to drain and refill without dropping the pan(still do a full service every 12k miles however).

Guru disagrees with me when I said to replace what you drained out because it may have been overfilled :rolleyes: OK...ASSUMING you have been driving around since the last service not overfilled, you will be OK. If Guru's logic holds, you MUST do a full service every 3k miles because it's possible the trans was last filled with Cheerwine. Also replace your filter because someone may have used a dish sponge instead of a OE filter and as long as we are pointing out long shot scenarios, be sure to clean out all the dead birds from the transmission pan that may have flown in by mistake.

[Ron]

This! This is my problem. How warm? How long to settle?Here's "the thing". Two actually. First the dipstick is bad about dragging along the inside of the fill pipe, making it hard to tell where the level actually is. Second, you have to allow the fluid to warm and expand before taking a reading. So, the trick is to start the engine and let it come to operating temperature. Check the level. If none shows, add one quart. Wait for the cool fluid to run down the inside walls of the pipe, (10 seconds ~ 1 minute). When you pull the stick, it should be wet near the end only. If not, repeat. Stop when it shows 1> quart lower than totally FULL. Take it for an easy ~5 minute drive.
At this point, every thing will be full of fluid. It will be expanded and thinner, which helps it flow down the tube faster and not collect on the stick as you insert it. Check the fluid and add to full mark w/o going over. (You can guess fairly well because the distance between the 2 main marks on most represent 1 quart.) If you go over a lot, drain it into a pan from the easiest place you can find (cooler line,..., plug).
From then on, all you have to do is check it (on level ground) after it has been driven a while .

[DrWin]

Do NOT ever take your DeLorean for a "power flush". This is a BS service designed to make money off of soccer moms and Gurus. It could seriously damage your transmission and best case do more harm than good. It's utterly ridiculous to even mention doing this.

Right - I wouldn't want to damage anything, that's basically why I'm asking for pointers about the entire thing.


If you are determined to change all your fluid, my solution (and one that I have been following for the past 3 or 4 years), just drain your fluid every other oil change. The plug is right there, it's no problem to drain and refill without dropping the pan(still do a full service every 12k miles however).

I think that's a pretty good idea. Relative to the rest of the cost of owning, operating and restoring a DeLorean, the cost of the oil and the copper washers is neligable.


Guru disagrees with me when I said to replace what you drained out because it may have been overfilled :rolleyes: OK...ASSUMING you have been driving around since the last service not overfilled, you will be OK. If Guru's logic holds, you MUST do a full service every 3k miles because it's possible the trans was last filled with Cheerwine. Also replace your filter because someone may have used a dish sponge instead of a OE filter and as long as we are pointing out long shot scenarios, be sure to clean out all the dead birds from the transmission pan that may have flown in by mistake.

Wait, are you telling me the seagull isn't in the pan for good luck? :)

[DrWin]

It is impossible to drain all of the fluid out unless you take it all apart. Much of it stays in the torque converter. All Dexron is backwards compatible, you probably won't find II anywhere anyway. It can be difficult to read the dipstick especially if it is overfilled. Follow the procedure in the manual. Don't forget the final drive must be checked separately and uses a different fluid. You cannot take the Renault manual directly and use it for the Delorean. Forget about the temp probe. Do not put back the same amount of fluid you took out, it may have been overfilled. Fill to mid-way between the add and full marks when hot on level ground. If you took the pan off you should either clean the old filter or replace it. Because you can't get all of the old fluid out you *could* go to a service station that has a power flush and have them flush the transmission. They hook up a machine that flushes the old fluid out and fills the transmission with fresh fluid. Best you can do without taking the transmission out and apart. Not really necessary unless your old fluid is very dark and burnt.

Good to know. I get Castrol ATF Dextron II from a speciality dealer, but there is very little point in doing that, it seems. Everyone seems to agree I should step it up to ATF Dextron III and be done with it. :)
I get that I can't just directly extrapolate from Renault Manual to aplying the same thing on a DeLorean, I just think it's very interesting to make this process more "stringent" instead of how it's descriped in the DeLorean workshop manual.
It feels sloppy, and I never feel confident that I did it right, which anoys me from a prefence perspective, but also because I', assuming that the automatic transmission is a weak/vulnerable/expensive part of the car.

[DrWin]

Stop when it shows 1> quart lower than totally FULL.
Thanks! Please elaborate. 1 quart lower than totally FULL. Do you consider "FULL" to be above the text WARM on the dipstick? Or where is that?


Check the fluid and add to full mark w/o going over. (You can guess fairly well because the distance between the 2 main marks on most represent 1 quart.)
Again please elaborate for the slow learner: What are the two main marks?

[Ron]

Thanks! Please elaborate. 1 quart lower than totally FULL. Do you consider "FULL" to be above the text WARM on the dipstick? Or where is that?


Again please elaborate for the slow learner: What are the two main marks?

I think I see the problem now...You don't have a dipstick with a "L" and a "F" as in the owner's manual.
I assume your's is like the one I've seen from DMCH. (Has, "COLD WARM HOT" and mystery lines on the other side ;-)
I would say that FULL would be just above "WARM".
The two marks would surround "WARM", I.E., COLD | WARM | HOT
Next time you change the fluid you will be able to tell exactly where it is.

[David T]

The power flush actually does work but you are right, on a really bad transmission it can dislodge enough dirt to really mess things up. As with any procedure, whoever is making the decision should be guided by experience, not profit motive. All too often an overzealous shop will recommend unnecessary work. On most newer cars the manufacturer doesn't recommend taking the pan down and changing the filter, they say to do a power flush. On some cars it is a very difficult and time consuming job to even drop the pan. Once a shop buys the equipment they want to try to use it on as many cars as they can so they get the machine to pay itself back quickly. You see the same thing happen when a shop buys an alignment rack. They start recommending it to every job as they go through the shop. As far as a Delorean is concerned, it is the easiest way to do a fluid change. Even doing what Michael suggested, changing the fluid several times in a short period, doesn't get all of the old fluid and dirt out but it is better than nothing. The best way to know what to do is to put some of the fluid on your fingers after checking the level. If it is dark, smells burnt, or feels gritty, it should be changed.

[DrWin]

I think I see the problem now...You don't have a dipstick with a "L" and a "F" as in the owner's manual.
I assume your's is like the one I've seen from DMCH. (Has, "COLD WARM HOT" and mystery lines on the other side ;-)
I would say that FULL would be just above "WARM".
The two marks would surround "WARM", I.E., COLD | WARM | HOT
Next time you change the fluid you will be able to tell exactly where it is.

Damn... I thought about this yesterday. B/c the dipstick I have, have no FULL marking and looks NOTHING like the one in the Renault manuals. I got to thinking wether the dipstick was original or not. Or wether it was possible to replace it with something that was easier to read.

You are absolutely right. I have COLD WARM HOT and mystery lines on the reverse. So I just fill it up until it hits between WARM and HOT with the engine idling?
After letting the oil settle down for a minute or two? This is REALLY helpfull, thanks!
(Also - where do I get the right dipstick?)

[DrWin]

The power flush actually does work but you are right, on a really bad transmission it can dislodge enough dirt to really mess things up. As with any procedure, whoever is making the decision should be guided by experience, not profit motive. All too often an overzealous shop will recommend unnecessary work. On most newer cars the manufacturer doesn't recommend taking the pan down and changing the filter, they say to do a power flush. On some cars it is a very difficult and time consuming job to even drop the pan. Once a shop buys the equipment they want to try to use it on as many cars as they can so they get the machine to pay itself back quickly. You see the same thing happen when a shop buys an alignment rack. They start recommending it to every job as they go through the shop. As far as a Delorean is concerned, it is the easiest way to do a fluid change. Even doing what Michael suggested, changing the fluid several times in a short period, doesn't get all of the old fluid and dirt out but it is better than nothing. The best way to know what to do is to put some of the fluid on your fingers after checking the level. If it is dark, smells burnt, or feels gritty, it should be changed.

That sounds like something to look out for. It's the old problem with everything looking like a nail to the guy with the new hammer. I actually met a (very drunk) classic car mechanic who wandered in to my garage while i was working on the car. He was very fast to recommend the powerflush service his employer does as a remedy for odd shifting. :) I happened to read the other day that late 1->2 when cold and shifting in and out of gears on low throttle was indicative of a shot governor. Link (https://support.delorean.com/kb/a69/automatic-transmission-shifting.aspx) I think i'd rather send DMCH my governor computer than go get flushed. I don't suspect that powerflushing the gearbox would help the electronics out.

[Jonathan]

Ok, so I've had my car for 14 years and still don't feel great about taking a good ATF level reading. For the same things you've mentioned. It's just harder than it seems it should be to see what the level is. Add to that how vague the answer is to how much fluid is needed after it's drained and it's no wonder people are concerned.

"If the level is low it slips, if it's overfilled it leaks." Yea, I wanted more specifics than that too. :)

I have that same COLD WARM HOT dipstick that you do. It came with my car so I don't know the history of which car got what design or had which markings originally. I replaced the dipstick tube not long ago and wanted to share some pictures. Since I didn't get a good answer to how much fluid to add when refilling, I wanted to see where the end of that dipstick goes into the pan.

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[Ron]

Damn... I thought about this yesterday. B/c the dipstick I have, have no FULL marking and looks NOTHING like the one in the Renault manuals. I got to thinking wether the dipstick was original or not. Or wether it was possible to replace it with something that was easier to read.

You are absolutely right. I have COLD WARM HOT and mystery lines on the reverse. So I just fill it up until it hits between WARM and HOT with the engine idling?
If you have driven it a bit after the engine is warm, yes.


After letting the oil settle down for a minute or two?
The time depends on how cold the engine/trans/fluid is. It may take a minute for it to drain down the fill tube when the trans/fluid is cold, but much shorter when warm.

If you have drained it and everything is cold, start the engine, add 3 quarts, wait a minute and check. It should be reach the cold-warm area. If not add ~1/2 quart. Once the engine is up to temp, double check and drive it around a bit (to heat up the trans/fluid). Finally bring it between warm and hot. Expect ~4 quarts total, plus any you may have drained out of the lines, converter, etc.
It's not all that critical -- Just don't drive it if it's not showing on the stick and don't top it off when the trans is cold.


(Also - where do I get the right dipstick?)
The dipstick (https://store.delorean.com/110134-auto-trans-dipstick.html) you have is right.

[DrWin]

Ok, so I've had my car for 14 years and still don't feel great about taking a good ATF level reading. For the same things you've mentioned. It's just harder than it seems it should be to see what the level is. Add to that how vague the answer is to how much fluid is needed after it's drained and it's no wonder people are concerned.

"If the level is low it slips, if it's overfilled it leaks." Yea, I wanted more specifics than that too. :)

I have that same COLD WARM HOT dipstick that you do. It came with my car so I don't know the history of which car got what design or had which markings originally. I replaced the dipstick tube not long ago and wanted to share some pictures. Since I didn't get a good answer to how much fluid to add when refilling, I wanted to see where the end of that dipstick goes into the pan.

Excactly my problem. I'd like to know what is going on, and when I can rest assured that I did it right.
Actually I wouldn't mind if it would leak - If it just blows off excess ATF I'd always go for overfull, since my understanding is that underfull will damage the transmission. I somehow got the impression that overfilling the transmission would also potentially damage something. (?)
Thanks for the pictures - care to share why you replaced the dipstick tube? Was it damaged?

[DrWin]

If you have driven it a bit after the engine is warm, yes.


The time depends on how cold the engine/trans/fluid is. It may take a minute for it to drain down the fill tube when the trans/fluid is cold, but much shorter when warm.

If you have drained it and everything is cold, start the engine, add 3 quarts, wait a minute and check. It should be reach the cold-warm area. If not add ~1/2 quart. Once the engine is up to temp, double check and drive it around a bit (to heat up the trans/fluid). Finally bring it between warm and hot. Expect ~4 quarts total, plus any you may have drained out of the lines, converter, etc.
It's not all that critical -- Just don't drive it if it's not showing on the stick and don't top it off when the trans is cold.


The dipstick (https://store.delorean.com/110134-auto-trans-dipstick.html) you have is right.

Thanks again, I feel much less uninformed now. Now I just have to sit tight and wait for my replacement dipstick. :)

[dmcnc]

Excactly my problem. I'd like to know what is going on, and when I can rest assured that I did it right.
Actually I wouldn't mind if it would leak - If it just blows off excess ATF I'd always go for overfull, since my understanding is that underfull will damage the transmission. I somehow got the impression that overfilling the transmission would also potentially damage something. (?)
Thanks for the pictures - care to share why you replaced the dipstick tube? Was it damaged?

The transmission will overheat if overfilled. That will damage the unit.

[Michael]

I wonder if other forums have a multiple page thread on the mysteries of replacing trans fluid?

Drain/replace/check. Done.

[David T]

The transmission will overheat if overfilled. That will damage the unit.
Too much fluid causes foaming and excessive leakage. When I check the level I do it several times. When you put the stick back in after wiping it off, only leave it all the way in (make sure it is ALL the way in) for no more than 2-3 seconds. I also like to move the shift lever in and out of each position while the motor is running before I check the level.

[Jonathan]

Thanks for the pictures - care to share why you replaced the dipstick tube? Was it damaged?

Cosmetic mostly. My old one was pretty grungy. And I wasn't convinced it was free of tiny pin hole leaks along the length. I fought ATF leaks for ages and that was one thing I wanted to change and rule out anyway. It was the seal at the end of the dipstick tube leaking and not the tube itself, however. Looks a lot better now anyway. I was under there for a considerable amount of time doing fuel line and filter work so cleaning up the ATF just happened then too.

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[DrWin]

The transmission will overheat if overfilled. That will damage the unit.

Thanks, that's propably why its necessary to check, and not just top up.
I just finished refilling mine and took the car for a drive. Erratic shifting, not a lot of torque at low speeds. Still mystified. Will look at it again later. :(

[David T]

Thanks, that's propably why its necessary to check, and not just top up.
I just finished refilling mine and took the car for a drive. Erratic shifting, not a lot of torque at low speeds. Still mystified. Will look at it again later. :(

These symptoms sound like you are starting out in 2nd and the shift computer is "acting up". First step would be to get a light box on the car and see how it is shifting. Once you can confirm the shift computer is the problem, you either fix or replace it.

[DrWin]

These symptoms sound like you are starting out in 2nd and the shift computer is "acting up". First step would be to get a light box on the car and see how it is shifting. Once you can confirm the shift computer is the problem, you either fix or replace it.

...I underfilled the transmission. Looked at it again today and got with the program. It finally dawned on me that I needed to know what the dipstick SHOULD look like when it came out of the oil. One thing was where L and F was on a stick that says COLD WARM HOT, like I talked to Ron about.

The other is what the oil itself should look like. I opened a bottle of ATF and stuck the dipstick in and looked at how that looked when it came out. Made me realise that when the ATF is cold it has to be a very thick film of oil to be a true reading. Also, I figured that orientation was important, because one side of the dipstick scrapes against the tube during insertion/removal, which can remove som oil, so it's actually only the side that is facing downwards/rearwards that's readable.

These two things together made me realise that I was way underfilled. I ended up putting more that an extra litre of ATF on the car, before actually getting (a thick layer of) oil on the dipstick at cold/rest.

I then proceed to adjust the fluid level according at cold to just below COLD, to between COLD & WARM after 5mins idle, then drove the car for 5-10mins and checked again to adjust to between WARM and HOT. All checks done after letting the car stand for 3mins, on a 2 post lift (to ensure it's horisontal) and efter going through all the gears on the selector with the engine idling.

That was yesterday evening and I just drove the car for the first real trip in 4 weeks. It shifted beautifully. Best it's been since I got it. And it lasted too, It wasn't a super long trip, just 65km, but enough that I feel confident that the fluid level is now correct. (Checked again after this trip. Still correct level, hits right between WARM and HOT after this drive, with the ATF very hot. It's harder to read when it's hot b/c it's thinner, but I'm sure I got it right.)

A big thank you to everyone that helped the ATF-amateur here understand what's going on. :)