Transaxle acting funny 2002 GS


Shadetree Mechanic
I am having a problem with our 2002 Buick Regal GS with 98k miles. Every now and then, like every few weeks, the transaxle will act up. In reverse or drive it will act like it is slipping, meaning the car will accelerate slowly while the revs just climb. Then all of a sudden it will clunk into gear and drive normally for days at a time. I thought the transmission fluid might be low, but it seems to be at the proper level and it is clean and pink. What else could be causing this behavior? The transmission fluid hasn't ever been changed so I thought I'd start there, but it seems more mechanical to me since it happens only intermittently and otherwise drives fine.
Your first step should be to check it for DTC's. Not all trans DTC's will turn on the "check engine/service engine soon" light.

Just guessing without any other information, I'd suspect a faulty pressure control solenoid.
I threw a scanner on it and there are no pending or active codes. It is just an $80 Actron code scanner, so maybe it won't tell me what I am looking for. I will check that solenoid out.
Yeah if it has a 1811 code it is a EPC solenoid.Ive changed 1000's of them in 4t65's.Will make them shift funny once in a great while without a code.
agreed , it sounds like a solenoid issue... cant be mechanical part or it would do it all the time.

the solenoids can be changed by dropping the cradle on the drivers side and removing the side cover , while in there change all 3 pressure ,shift & TCC

triple edge performance is the top guy on these trans. Dave is a member here also so consider buying your parts here:

Solenoids and Valves
Thanks! I will contact Dave for the parts I need. Trying to get things cleared up by the first snowfall. :)
I still haven't gotten around to doing this. What am I looking at in terms of time and difficulty just doing the PCS?
I might also suggest an input clutch piston getting worn out. This can have an intermittent affect as well. I think that triple edge has some troubleshooting stuff on their website that you could use to zone in on the problem as well.

Just a thought. I had a similar fialure in my car, however it eventually just wouldn't move other than once in a very long while.
It almost seems like after you spend all that time getting to the cover to replace solenoids and things that you'd be further ahead just getting a reman trans with a warranty and putting it in. I am guessing you'd be in it for at least $850 to do just the PCS at a shop.

One thing I might try is Seafoam TransTune. Some people have had luck flushing with that stuff and then putting in fresh fluid. I don't like snakeoil tricks, but I have read at more than one place that this has worked for gummed solenoids in these transmissions.
Well, that was a waste of time and money. The Seafoam didn't do a darn thing and I wasted $30 on new fluid since I replaced fluid post flush that was only a few months old. I do not get any codes on my Actron scanner when I was expecting a P1811. (unless you need a more sophisticated code puller to see this code) It is taking a long time to shift from 1-2, i.e. the rpms shoot up and it eventually falls into gear. It does this 75% of the time and sometimes slips for a second from a stop and harshly grabs and goes. I am now thinking it is more than a solenoid change and this 107k transmission is ready to melt down. This is beyond me, so I guess I will have to take it to a trans shop and bite the bullet. This is all when we were planning on trading it in on a 2011 Turbo Regal. :(
Here's an update. I went to two transmission shops this morning and luckily both were staffed by nice knowledgeable people. You never know what you are going to get. I rarely ever have to go to shops, but transmissions are an exception. The first shop put a computer on the car and we drove it around for a while. It was elongating the 1-2 shift every time and staying in 2 at a stop. Upon acceleration, it would shift from 2-1 and then elongate the 1-2 shift. The car set no codes at all, which surprised the tech because he thought it would set the code for long shift. He said it could be two things. They could clean up and inspect the valve body for $125, but if there isn't a problem with it, I am likely looking at a rebuild as new at $2000. He didn't think the vb would be the culprit because a plugged vb would usually set a solenoid code.

At shop #2, the guy put the car on a scanner and we drove again. Of course, the same symptoms showed up. He was also surprised that no codes were being set since he felt it should at least pop a P1811 or similar. He felt like it was mechanical in nature and without seeing the internals, he would guess it could be fixed with the clutch piston (as mentioned by a member above) for $800 or a complete rebuild/warranty for $1500.

I guess I am probably going to have to go with a rebuild at shop #2 or possibly just get one from TripleEdge depending on shipping charges. There really isn't anything else I can do. Since most of the job is labor to r/r, it doesn't make sense to just replace the piston and hope everything else holds up with 107k on it. It just troubles me that no codes are being set but I have no idea if that matters in this case.

Just when we were getting ready to trade this car in. :( Even in excellent condition, this car only has a $4000 trade in value, so now I'd be cut down to only getting $2k out of it after all is said and done.

Interestingly enough, both shops said they see this trans a lot and they start to act up around 90k. I can drive the car just fine if I manually shift it.
Here is what Dave at TripleEdge said in response to an e-mailed question. I think I am just going to buy a replacement trans from him and call it a day. He makes sense! I am just posting this for future reference for forum members with the same problems. I hope Dave doesn't mind me posting his response to me, but I feel it is a valuable learning tool!

Hi Steve,

Generally the pcm wants to see shift times under .65 seconds and if a few consective shift times are longer than this then code P1811 will set for max adapt shift and then the transmission will be working in max line pressure to prevent slippage. If shift times were not taking this long the code will not set. If the pcm has been modified or reprogrammed at any point then someone could have dissabled the error code to set- and YES this is something I have seen before which can make diagnosing problems a nightmare. I have tuning software so I have the ability to read a pcm feel and check for something like this. If everything is 100% stock and the shift times are taking longer than they should and no code is setting then there could be another reason for this. There is a list of variables that have to be met before the pcm will run its tests required to cause a code to set. Long 1-2 shifts have always plagued these transmissions, they just were not set up too well from the factory and a few tweaks will make a pretty noticable improvement but requires tearing the trans apart. The 1-2 clutch clearance is way too loose from the factory and just gets worse with age and mileage so the shift kits worse also. A valve body problem alone is doubtful to cause this. The big question here is- are you willing to spend $800+ to repair a transmission with over 100K miles on it? There are several wear problem areas of these transmissions and fixing one problem is not going to address everything and then shortly down the road you could be looking at more $$$ to fix more problems. We suggest to our customers if the trans has over 100K miles on it that it is best for a rebuild and we wont go inside for repairs as there are just too many concern areas that we cannot warranty against failures and had to charge someone that much money to find out in a month they need a rebuild anyways. Just my $.02 but some food for thought.

David Norris

Website: Triple Edge Performance - Home Page
Just when we were getting ready to trade this car in. :(

If you really enjoy having a car payment, the dealer doesn't care how the trans shifts on your trade in. Have you seen what kind of deal you can work up "before" you decide to repair the trans?