Slippage

[SIMid]

Hi everyone,

Finally got my leak fixed and she's holding all her liquids. But I went to a car show over the weekend and on the way home, she started slipping on the uphills close to home. It was a pretty warm day (38 degrees C) and a fairly long drive as well. Maybe 250kms all up.

Usually when she runs low on fluid, she starts to slip. This case, the fluid level was good. Spoke to my mechanic just then and he's guessing that the box may have got a touch too warm, it's shouldn't though, but a possibility. He told me to drive her this comign weekend and see if it plays up again.

Ideas anyone? Would a transmission cooler be worth a modification?

[Bitsyncmaster]

I assume your taking about the auto transmission. Have you checked the fluid when the tranny is warm, engine is on idling in park?

[SIMid]

Have you checked the fluid when the tranny is warm, engine is on idling in park?

I couldn't check it when it was slipping as I got home late at night. I did check it the following day after I had warmed her up, looked okay. I should recheck it when she starts slipping, in daylight.

[David T]

Very bad to dive on a slipping auto trans. You can wear the clutch packs out quickly. The more the clutch packs wear the more junk gets into the filter, the lower the pressure, the more they wear. First, don't drive on a slipping trans. Next, check the level as per the Workshop Manual. Finally check the line pressure. If it is low (and that is what I am guessing) pull the filter and cut it open to clean it. There is a procedure on how to do it and reuse it. If that doesn't get the line pressure up and stop the slipping you will have to pull the transmission and rebuild it.
David Teitelbaum

[deloumis]

Usually when she runs low on fluid, she starts to slip.

You may want to clean your filter as David said. Also if you have ran it multiple times with low fluid could be you burnt out clutches. Not a good idea to run with low fluid.

[Ron]

The only thing useful you might gain by checking it while it is slipping is, when comparing to full when it was warm (at normal operating temperature), you find it reads a lot more...well over the full mark, indicating it is getting too hot (trans fluid expands a lot, relatively). If the fluid looks good (clear and fairly pink, with no minute specks etc when looking at it on white paper, or better yet, through a glass container), I'd check the pressure before I drove it another foot because the clutches are nothing to brag about when new. IMO, the filter has a lot more capacity than it may sound in the above posts, ie if there is enough clutch material in the filter to affect the pressure, it is probably past rebuild time.

[SIMid]

Thanks for the responses. I had the leak fixed several weeks ago and he had also cleaned out the filter. My assumption is the heating of the transfluid to a point where she becomes very low and then, slips on the hills due to the starvation in the box. I'm going to give her another long drive this weekend and re-check the level.

I'm suspecting low fluids in the box which I cannot get an accurate reading till she warms up properly.

[SIMid]

Ok,

Warmed up the engine and transmission, topped up the fluids (minimal) and took her for a drive. After several hours of motoring, she started to slip on the climbs in 3rd gear. I had to slow down for the box to drop a gear so that I could accelerate back up. But then, on some hills, she is fine in 3rd gear with no slippage. I am having problems getting access to the second reservoir to check it as I don't have ramps or a hoist. I'm hoping on the weekend, or the following week to pay my mechanic a visit to stick up up there to check it. But I had the box serviced not long ago by him, so the levels in both should be fine and correct.

Are there other things I need to check or ask a specialists to check/test? I had the filter cleaned out, so all pipes should be clean as well (something about a breather pipe?)

Please don't tell me that I need to rebuild the box. If I do, have previous owners had any issues with this box compared to the norms? Will it be a headache for an auto rebuilder or be just a normal box for them to rebuild?

[Jonathan]

Simon,

Barring any wishful thinking, that sounds a lot like the shift computer governor to me. I don't know much about rebuilding them, but I know how to send DMCMW $250 for a new and improved one and after it went in, I never thought about it again.

If you can get your car on a lift, look over the different sections of that wiring harness and see if any of it got melted by the exhaust. That's easy enough to check for now.

[SIMid]

Simon,

Barring any wishful thinking, that sounds a lot like the shift computer governor to me. I don't know much about rebuilding them, but I know how to send DMCMW $250 for a new and improved one and after it went in, I never thought about it again.

If you can get your car on a lift, look over the different sections of that wiring harness and see if any of it got melted by the exhaust. That's easy enough to check for now.

That's what I was thinking Jonathan, but she shifts fine and at the right time when driving normally. With I'm cruising along in 3rd, get to a hill and squeeze the throttle, the revs rise, but no acceleration. So I'm presuming it's mechanical. Toby had replaced the Governor about 5 years ago and she only travelled 3000 miles since. The PO had issues with it shifting. Plus the issue is random, so if it was a wiring issue, it would be happen straight away before the box warms up.

Had a quick conversation on the blower with my mechanic and he said sounds like it's losing pressure when in top gear, possible an "o" ring leakage, but like with anything that's sealed, you need to open it up to check it. He couldn't give me a price as no one here in OZ has worked on a Delorean, so it could cost me $2K right up to $5K. Fark.

But I should take it to him, stick her on the hoist to take a look at the wiring to check it to be certain.