94 PA Base Trans Questions

[Mastercarpentry]

So the old boy has a lot of issues which I'm working out because I love this car. Some obscure answers came from here than solved some real hair-pullers- thanks for sharing the expertise!

Now the specifics: 266+K miles, never serviced the trans (used car and left it alone) but now the shift points are much lower than they used to be and it will not drop into passing gear. The TC seems to lock and unlock properly (most of the time- sometimes it will not lock even at 70 on level roads). The fluid is full and what you'd expect at this point- dirty and very slightly burnt smell from normal wear and no servicing. Three possible affiliated problems may be that the too-cold thermostat won't let the PCM go past 'cold' mode, old vacuum lines leak or collapse (fixing all that today) and the eng temp sensor may not be in spec (original part, gauge reads lower that thermostat temp). No slipping, harsh shifts or other issues. I may go so far as changing the filter while saving and straining as much old old fluid as I can (new fluid only to top up)so that I don't clean out all the sludge which is keeping everything in the tranny sealed up and working Also replacing leaking UIM/LIM gaskets today- hope I don't need the usual EGR pipe fix

Even a much as I love this car I expect only a couple more years service before a major engine/tranny problem relegates it to the 'no longer worth fixing' category as the rest of it is a little rough, making any repairs over $1000 questionable. I'm a decent wrencher but have no shop nor specialized tools for a DIY trans rebuild so when it finally goes for good, so does the car Just looking to make that happen as far into the future as I can

Thanks in advance!
Phil

[Mastercarpentry]

Update: Got the UIM and LIM gaskets in, what a chore getting everything out of the way and then back! The bolt holding the EGR pipe broke and a plastic vacuum fitting broke (tomorrow's job) so no checking the shifting just yet, but oddly the rubber thermostat ring has shrunk and split, letting coolant flow around it which was causing the low temp readings. Everything else was fine. EGR seemed to be working freely. The battery is still disconnected so I'm going through the 'reset' procedure for the PCM tomorrow.

Wish me luck!
Phil

[HotZ28]

The only "reset procedure" would be to drive the car and let it relearn while driving at your normal driving parameters. As far as the trans, drop the pan & change the filter & add approx 7-qts of fluid. Drive for about 5-K then do it again. You may have an PCM problem, but it never hurts to do proper maintenance first. Good Luck.

[Mastercarpentry]

Originally Posted by HotZ28

The only "reset procedure" would be to drive the car and let it relearn while driving at your normal driving parameters.

I saw the thread on doing this and it seems like a good idea. After all, the engine is far from new so the A/F etc it needs aren't going to be what the default settings are anymore.

As far as the trans, drop the pan & change the filter & add approx 7-qts of fluid. Drive for about 5-K then do it again. You may have an PCM problem, but it never hurts to to proper maintenance first. Good Luck.

My main concern here is the detergent action of the new fluid. At this point the only thing letting everything seal up is gunk- clean it out and the internal leaks will stop it from working at all. I've had that happen to me once and seen it happen dozens of times, which is why I really don't want to change the fluid- only the filter. And that only if it's absolutely necessary. Let's face it: at 266K it ain't too long for the world no matter what! I just need to get every mile out of it that I can.

I knew the un-maintained history of this car when I got it 140K ago. I've gotten 6 years of service out of it with about $400 a year in repair/maintenance costs which is about as good as you can get. Nothing last forever but I was wondering about this car being an exception as good as it has been till now!

Just test drove the old boy today and he runs a lot better. There was a leak between a water passage and an intake port on the LIM gasket- you could see where it washed across. The car shifted properly for normal driving but still no passing gear. A post-drive check showed a split vacuum line to the CC unit- fixed that and now I've gor 4 gears, no kickdown, and no TC lockup. I've got another good PCM so I may swap it out if nothing else seems to work. About 20 miles total driving, just to see if it cleared up and the TC locked properly once then not again. I read where a brakelight switch might cause this so I checked that and it's OK- clean inside and all contacts switching properly.


Phil

[Mastercarpentry]

One last update before I let the thread die
Fixed vacuum leak, tranny shifts fine 1-2-3 any amount of throttle, but no OD, and no kickdown when floored in any gear- warm or cold. No slippage ever, no chatter ever. Prior to current problem, occasionally the OD-3 downshift going uphill was somewhat sensitive occasionally but never any real pattern to that- just a personality quirk that didn't hang around The rascal always did this since 50K when my sister bought it used (so I know the car's history from that point on). The OD was working when I parked it with the charging problem 8 months ago.

It seems that this has to be something specific to the OD, not just general wear. I'm pretty sure the O2 sensor is bad and I need to clean the MAF sensor still. Not having a tranny scan tool what should I check from here? Searching "4T60E" got me the resistance values to check the internal solenoids (my next and almost last step). If they check good, I'm swapping the PCM again. I had (past tense) charging issues and swapping the PCM back then made no difference in anything so I put the existing one back- OD still worked with a manually charged battery either PCM. New everything for charging now, all primary wiring fine and an extra block-to-chassis ground just to be sure. Door-sill ground busses repaired and fine (if that matters). Going to use a friend's PCM scan tool to see what codes I've still got there, but after that I'm lost. That's about all I can tell you about this one.

I don't want a car just to use around town where it never leaves 3RD. I need the old bugger to have an OD for highway speeds. My last plea for HELP here with this problem. Anyone?

Phil

[Jrs3800]

Honestly sounds like your TPS is going bad... I would check that with the scan tool and see if it actuates smoothly...