Shifting problems

Hello all! I'm so glad I found these forums! I post at C&D forums, but that's about it. Anyway, read some threads and it seems that people are having similar problems with their late model Centuries. Anyway, here's mine.

My car is a Century 2000, 3.1L engine with the 4T65E autotrans. Power everything, ABS, traction control, 62,700 miles. If you need any more info, let me know.

I had the PC Solenoid Valve replaced (in September) -- I had the P1811 Longshift code. Before this was done, the vehicle shifted erratically, shuddered and went into limp-home mode. I thought the replacement of the PCS Valve would cure this, but...

The vehicle still shifts hard, here's what/when it happens. Now that the temperature's dropped, I've noticed that the car shifts very smoothly, since the engine is cooler. I noticed this a few weks ago. Of course, as the engine heats up, the shifts aren't nearly as smooth. This isn't to say that when the engine is warm the shifts are ALWAYS harsh, but in general they are. Another detail I've noticed: the harsh shifts generally occur from the 1-2 upshift (almost always), sometimes from the 2-3 upshift, and rarely ever from the 3-4 upshift. Downshifts are invisible.

When travelling at speeds of about 45 or above, when I press the accelerator halfway or more to the floor, I can detect a shudder; it's not as bad as before the PCS Valve was replaced, but it's definitely there. It's very noticeable when climbing uphill. Right in that 45-50 range is where it's the worst. I've taken it back to the dealer since and no codes have come up, so they refuse to do any work.

Also, don't know if it's related. About a week after the PCS valve was replaced the car broke down. I was making a turn, going about 10 mph, when something from the engine area began vibrating and making a grinding noise. I hit the barkes but they didn't really work, the car continued to pull me forward, bucking and lurching. The steering wheel was very difficult to turn, like pulling it through cement. When the car finally stopped, it died. The lights and radio still worked fine. I restarted the car -- no problem. However when put in gear the car died. Had it towed to the dealer (this was around midnight), and they looked at it the next day, but the car started for them, drove, and they could find nothing wrong with it :confused: !? The problem has not happened since. I wasn't sure if this problem was caused or related to my transmission troubles.

Dealer has no clue (I don't trust them, but I have a warranty on this vehicle and the warranty company will only pay for the work to be done at certified locations). It's been suggested that the PCM (Powertrain Control Module?) may be bad, or that I have bad grounds. I had the tranny fluid/filter changed when the PCSV work was done, so I seriously doubt that is the issue. Any suggestions would be appreciated. I'm taking the car to my trusted mechanic tomorrow to see what his thoughts are. Reading through these forums, it seems others have had this problem. If any of you with the same problems have found a cure, let me know, it would be appreciated! Thanks for the future advice/help!

Oh, last question -- does anyone else with a Century have problems with the steering wheel being cocked to one side. Let me know, thanks! :smile:

It appears there are a number of us with the same harsh shifting problems. I've been living with mine for a while, but I had an additional problem appear recently (see 2000 Century TCC issue thread). There was a suggestion posted there about an additive that I am planning to try once I find where they sell the stuff. You're lucky to have a warranty, I don't.
It seems there ought to be a recall on this. Its not only Buick, all GM FWD cars using the 4T65-E potentially can have the problem. There is a GM service bulletin out on this which says change the PCM solenoid, but you changed yours and it didn't fix the problem. You'd think GM would have gotten automatic transmissions right by now. In fact they did once. I had a Chevy Pickup that had 260K miles when I sold it and the transmission was still workling fine.

Hey, thanks for the reply. I went to that website which sold the Tranny protectant. I agree with the person who posted -- it's probably just a deterrent, but I may try it -- I have nothing to lose. Unfortunately, reading through these posts it seems like there are so many problems that the exact problem may be difficult to solve -- discouraging to say the least. I agree, GM should recall these transmissions, with all of these problems. The PCS Valve service bulletin must cover millions of GM cars with the 4T65E transmission, the list is huge.

You're right, I'm lucky to have the warranty. It cost about $1,100 dollars (added it on to my car loan, so I didn't pay it all at once). Seeing as how I've ran up $800.00 in repairs since June, I'd say it's definitely been worth it.

Check online, search 4765-e , looing thgouh your search finds, you should find a re all for late model Buicks, (2000 + up)

I had the same transmission problems as you describe rough upshifts. Never quit on me or went into limp mode though. At 48K miles and a cost of $600, the GM dealer replaced the pressure control solenoid in my 2000 Century. Worked great for about 1 year then started the rough shifting again. With no warranty and already $600 in it I decided to live with it. Serviceing the transaxle yearly, new fluid and filter seems to help, but does not cure. Seems the dirtier the fluid the more frequent the problem. Any info on the recall that COOKMAN7325 mentioned in his reply? I haven't been able to come with anything.

Make sure that the dealer cleared the TAPS info in the PCM my wifes car did this and shifted worse after the solenoid was replaced. Took it back and dealer explained that they forgot to clear the data. The computer has to "relearn" your driving habits to adapt the shifts. Hope this helps....

Hi,

Check it out:

http://www.automotiveforums.com/vbu...884#post2684884
http://www.automotiveforums.com/vbu...ght=2000+Impala

Thanks :)

TG.

Hi,

Check it out:

http://www.automotiveforums.com/vbu...884#post2684884
http://www.automotiveforums.com/vbu...ght=2000+Impala

Thanks :)

TG.
Niether one of your posted web page links worked, can you repost the corrected links?

Thanks

Niether one of your posted web page links worked, can you repost the corrected links?

Thanks


Try this one:

http://www.automotiveforums.com/vbulletin/search.php?searchid=784885

Cheers,

TG

Niether one of your posted web page links worked, can you repost the corrected links?

Thanks


Okay, here's the solution:

Goto the Impala section of the forum and in the search space type in "tgenerl" without the brackets and click on "go"...

Cheers,

TG

I have a 95 chevy 3/4 ton truck with 201000 miles the tranny has been rebuilt twice and now I am have shifting problems. THe truck runs great but sometimes it bets stuck in 3rd gesr. need so honest advise.