TT transmission slip / complete loss of power

[Corvidae]

So my 93 TT is finally back on the ground after pulling / replacing the engine, but the transmission is having a pretty serious issue. It's difficult to describe what's going on, so here's a sample sequence of events:

* Start car, let idle for a few seconds
* Put car in drive, creep forward (normal)
* Apply brakes, put into reverse, creep backward (normal)
* Place in park, rev engine for several seconds (above ~2500RPM seems to do it; I was using 4000 for testing) then release throttle
* Place car in drive, try to creep forward (nothing happens)
* Apply gas (have to rev engine to get it to start moving at all, very sluggish)
* Apply brakes, place car in reverse (either does nothing without revving engine or continues to move forward)
* Turn off car for 5 seconds or so
* Start car, attempt to creep forward again (works fine)

This happens while driving, as well (stopping at a light will kill any power to the rear wheels, but restarting the car clears it up again). transmission fluid is good (have drained and refilled twice now, has looked good both times). Neither the ECU nor the TCM are showing any codes. Any thoughts on what else to check? The car ran just fine before the engine was pulled (last July), and it's been sitting from then until just now. I'd prefer not to have to drain the fluid again (it's getting expensive), but I will if necessary.

Thanks in advance.

[mrmoose]

when you pulled the engine did you leave the torque convertor on the transmission? if not might need to be filled more. otherwise im not auto expert but maybe its got a clogged filter screen? when you turn if off its not sucking in oil and thus the debris drops back down? no idea just a thought.


also on a side note could be a failing solenoid or valve in the transmission.... does it work better or worse when warm or cold?

[Corvidae]

I did leave the torque converter on, yeah. Just disconnected at the flex plate / bellhousing and pulled the whole transmission back. Didn't crack it open, either.

The filter's really the only thing we can think of. I have one arriving tomorrow; will check it out and let you know.

Both times it's happened (the first required a tow... ugh) the engine has been warm, but I don't know if it's related. A solenoid shouldn't be affected by sitting, but could a valve fail having not been activated in over a year (I really hope not)?

[t.mcginley.jr]

I could be wrong but it sounds like an electrical problem if turning the car off/on clears up the problem. Is the trans harness/connector in good condition?

[Ace2cool]

No, it sounds a lot like what happened to my 2+2 when I lost reverse gear. When I revved it up to about 4000, it finally caught and squealed the tires. I took it to a transmission shop, since I know approximately nothing about A/T's, and they said that my filter got clogged, and that basically burnt out everything upline of that.

[Corvidae]

t.mcginley.jr: The electrical connections all look just fine. The AT diagnostics say there are no faults.

Ace2cool: Eep. When you say "burned out," you mean actually burned out, right? Do you think that driving it for an hour at most could have done significant damage? I really hope not...

I'm checking the filter tonight. With any luck, that'll clear up the problem.

[Ace2cool]

I'm not sure, that was just the term they used to describe it. I know it needed a new solenoid and a torque converter for sure. This has been 4 years ago though, so I don't remember exactly what all was replaced.

[Corvidae]

Okay, whew. The solenoid seems to check out fine and the TC works as long as the revolutions stay low, so hopefully nothing's actually damaged.

I'll let you guys know what happens. Thanks for the responses.

[nissanfreak12]

How do you know the solenoids are good? and The TC? The trans diagnostics sometimes don't always tell the truth. It could very well be the start of a failing AT ecu, or at least poor grounds or connections.

How is the TPS? Has it been replaced or adjusted?

[Corvidae]

Re: the solenoids / TC: I don't know. They _were_ just fine before the engine pull and the car drives normally as long as the RPMs don't get too high. The FSM has ways to check the solenoids, but is there a way to check the TC without physically pulling it? I don't think there is, but...

The TPS was never touched (short of disconnecting the harness so it could come out with the engine).

[Corvidae]

Turns out it was a nearly-clogged filter. It didn't look like the pan had ever been dropped; still had the paper gasket. The fluid in the pan was untouched, while when I disconnected the filter, I got a lot of darker stuff out. There's a slight shuddering now under acceleration, but I think it's air-related. She holds up under high-RPM conditions, though.

Thanks again for the leads! I have my baby back.

[Ace2cool]

Awesome. Glad to hear you got it sorted. Also glad to hear it wasn't something along the lines of what happened to me.

[t.mcginley.jr]

Woo nice! Did you see what came out of the clogged filter? Or was it just caked up with old ATF?

[Corvidae]

It was just that iron "goo"... tiny tiny iron filings soaked in ATF. No flakes or anything. Pretty typical for a transmission that had likely never been serviced.