Transmission problem?

Hi,
2000 Grand Prix 3.8 GT approx 75K miles. This is a very intermittent problem. Getting what sounds like transmission whine or gear noise along with harder than normal shifts. It’s more evident at low speeds but appears to be in all gears and can be heard at highway speeds. It happened yesterday on the first 45 minutes of a three hour road trip and then totally cleared for the remainder of the drive. When the trouble is “in” the whine can also be heard when reving the engine in park. Fluid level is normal . This has happened twice in 60 days so I’m hesitant to spend the diagnostic fees when the trouble is clear. Any ideas?

Thanks
Bob…

You probably have a DTC error code stored related to a bad PCS - Pressure Control solenoid so getting it scanned will retrieve it. These codes do not trigger the SES light but will cause high line pressure which results in the whining sound and harsh shifting.

Sea Foam or Lubegard tranny additive may help so it is worth a try. If that doesn't work then a new PCS solenoid will. A GM TSB has been out on this problem for years now.

bnaylor3400,
Tnx for your input - I'm sure it will help when I take the vehicle in for work . Is their a way for me to get a copy of that TSB other than talking to a dealer.

bob...

bnaylor3400,
Tnx for your input - I'm sure it will help when I take the vehicle in for work . Is their a way for me to get a copy of that TSB other than talking to a dealer.

bob...

No problem and you are welcome. I can post it later after work. Basically, it requires replacement due to whining, harsh upshifts, launch shudder, P01811 slip DTC error, etc. The tranny side cover has to be removed and the PCS solenoid replaced. Solenoid runs around $50. It is located on the left hand side of the valve body. Can be done DIY but most people take it to a tranny shop. Tranny does not have to be pulled out completely but it is tedious work because everything in the way of removing the side cover has to be removed and then re-installed. New side cover gaskets are required too.

MAN!!! Why doesn't GM own up on this problem and do a recall! I know they are in bad shape...but, if this is any indication of how they will treat people when they have problems...how can they expect anyone to buy from them agian? I understand why you guys get tired of answering tranny questions now....cause everone has or will have them!

bnaylor3400,

Found a local shop that will scan the codes no charge. Will let you know of the outcome.

bob...

bnaylor3400,

Found a local shop that will scan the codes no charge. Will let you know of the outcome.

bob...

Sounds good. Here is the TSB i mentioned earlier. Good luck!


A/T - 4T65E Harsh Shifts/Shudders/Slips/DTC's Set
File In Section: 07 - Transmission/Transaxle
Bulletin No.: 0O-07-30-002B
Date: July, 2002
TECHNICAL
Subject:
Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly)
Models:
1997-1999 Buick Riviera
1997-2002 Buick Park Avenue
1998-2002 Buick LeSabre
1999-2002 Buick Regal
2000-2002 Buick Century
2002 Buick Rendezvous
1997-2001 Chevrolet Lumina
1997-2002 Chevrolet Monte Carlo
1999-2002 Chevrolet Venture
2000-2002 Chevrolet Impala
1997-1999 Oldsmobile Eighty Eight
1997-2002 Oldsmobile Silhouette
1998-2002 Oldsmobile Intrigue
2001-2002 Oldsmobile Aurora (3.5L)
1997-2002 Pontiac Bonneville, Grand Prix
1999-2002 Pontiac Transport/Montana
2001-2002 Pontiac Aztek
with Hydra-Matic 4T65-E (RPOs MN3, MN7, M15, M76)
This bulletin is being revised to add additional models and model years. Please discard Corporate Bulletin Number 00-07-30-002A (Section 07 - Transmission/Transaxle).
Condition
Some owners of the above vehicles with a HydraMatic 4T65-E transaxle may comment on harsh upshifts or harsh garage shifts, soft shifts, shudders on hard acceleration, or shifts erratic. These conditions may appear intermittently or set a DTC P1811 or P0748. During diagnosis, a low or high line pressure (actual versus desired) may be observed.
Cause
The above condition may be due to any one of the following which may affect line pressure output:
^ Sediment inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind.
^ Sediment in the valve body, causing the torque signal regulator valve to stick.
^ Incorrect transaxle oil level.

MAN!!! Why doesn't GM own up on this problem and do a recall! I know they are in bad shape...but, if this is any indication of how they will treat people when they have problems...how can they expect anyone to buy from them agian? I understand why you guys get tired of answering tranny questions now....cause everone has or will have them!

The reason why it's not a recall is it's not a safety issue. Also, the hard shifts actually aren't "bad" for the tranny, they're a driver annoyance. There's less clutch wear when the tranny shifts firm as opposed to the soft "smooth" shift that everyone thinks is so nice.

With that said, PCS replacement is still recommended and it just takes time disconnecting everything but the actual replacement of the solenoid is as easy as can be.

Also, the hard shifts actually aren't "bad" for the tranny, they're a driver annoyance. There's less clutch wear when the tranny shifts firm as opposed to the soft "smooth" shift that everyone thinks is so nice.

I disagree. Early detection and resolution will lead to prolonged tranny life. Excessively low or high line pressure is not good period. Also, the harsh shifts will cause premature drivetrain failure. I've experienced harsh shifts due to a bad PCS solenoid that will cause your head to hit the headliner. Defintely not good or a petty annoyance. I'll settle with normal shifting any day of the week and making sure I get my monies worth out of the tranny and car overall.

Okay, I guess I should have clarified a bit more. If it's a "harsh" shift that feels like the tranny has a shift kit than it's not that much of an issue.

If it's a harsh shift that feels like going from neutral to reverse while ever so slightly rolling down a hill then yeah that's not too great on the drivetrain.

Firm shifts are just that many less milliseconds the clutches are slipping. As long as it's not excessive the drivetrain will be OK.

Based on how our 99 Regal GS is shifting from 2-3 and sometimes 3-4 in hot weather it's firm, but not enough to cause drivetrain damage.

Okay, I guess I should have clarified a bit more. If it's a "harsh" shift that feels like the tranny has a shift kit than it's not that much of an issue.

If it's a harsh shift that feels like going from neutral to reverse while ever so slightly rolling down a hill then yeah that's not too great on the drivetrain.

Firm shifts are just that many less milliseconds the clutches are slipping. As long as it's not excessive the drivetrain will be OK.

Based on how our 99 Regal GS is shifting from 2-3 and sometimes 3-4 in hot weather it's firm, but not enough to cause drivetrain damage.

StevePT, all I can say is when you get a harsh or HARD shift due to a PCS solenoid you will know it. And if your Regal GS exhibits that now then you should consider getting it resolved because any erratic shifting on a 4T65E tranny is abnormal. I have 3 "W" bodies, a '97 GTP, '01 Regal GS and '99 Regals LS and they all shift flawlessly. One of them had a bad PCS solenoid in which I replaced DIY and I am glad I got it on time.

Most GP owners that post problems with their trannies know it too and good thing they are seeking help.

Yes the PCS will cause hard shifts more so when hot but it can occur at anytime. We have had them in ALOT for a bad PCS. Some shift hard some just plain act strange other will start violently bumping and shaking a road speed. a MAX ADAPT code I don’t believe will set a SES light but auto zone and parts America will scan it for free! The other possibilities of a whine are bad bearings but where it is intermittently I would not really say you had a bearing issue.

Hmm. My 1999 GP GT with 76k miles on it has the same problem from time to time. When it is in stop-and-go traffic transmission starts shifting rough through all gears. If you start accelerating to normal speeds problem goes away. I checked transmission fluid level and its condition, seems fine. There are no rattles or hesitation during the downshifting or acceleration.

Is this a problem worth taking the car to the shop ?

Yes the PCS will cause hard shifts more so when hot but it can occur at anytime. We have had them in ALOT for a bad PCS. Some shift hard some just plain act strange other will start violently bumping and shaking a road speed. a MAX ADAPT code I don’t believe will set a SES light but auto zone and parts America will scan it for free! The other possibilities of a whine are bad bearings but where it is intermittently I would not really say you had a bearing issue.

Thanks for weighing in Troy1. Good to have a tranny repair tech on board.

For anyone interested in the how, what, why of a PCS solenoid problem, here is a good link that shows pics of a defective PCS solenoid out of a 4T65E.

http://www.automotiveforums.com/vbulletin/showthread.php?t=398499

bnaylor3400,
Got a shop to pull the code and they came up with 1811 (maximun adapt & long shift). A few questions:
a: since I don't have the expertise or equipment to attempt the repair would it be wise to sink the several hundred for this or considering the mileage (75K) and the fact that many of these die before 100K, do a total rebuild?
b: what is a round figure price to rebuild the 4T65E?
c: another issue I have with the vehicle is it exhibits a surging problem during slight throttle application at highway speed. It can be felt and seen on the tach as it will vary a few hundred rpm. After backing off on level road all is well. If this is transmission related it might be another reason to rebuild.

thanks in advance,
bob...

bnaylor3400,
Got a shop to pull the code and they came up with 1811 (maximun adapt & long shift). A few questions:
a: since I don't have the expertise or equipment to attempt the repair would it be wise to sink the several hundred for this or considering the mileage (75K) and the fact that many of these die before 100K, do a total rebuild?
b: what is a round figure price to rebuild the 4T65E?
c: another issue I have with the vehicle is it exhibits a surging problem during slight throttle application at highway speed. It can be felt and seen on the tach as it will vary a few hundred rpm. After backing off on level road all is well. If this is transmission related it might be another reason to rebuild.

thanks in advance,
bob...

Well, that's not good news but it does confirm PCS solenoid and consistent with the GM TSB. The PCS solenoid started acting up in my GTP a few years ago. I'm fortunate to DIY since I have been wrenching on cars for over thirty years and have a technical background but I would not recommend doing it in your situation. A PCS replacement alone will run around $400 - $500. With 75K miles maybe you caught it on time. I had around 68K miles on my GTP. The tranny shop tried to talk me into a rebuild $1500 - $2000. I decided not to do it and have not regretted the decision. I now have 92K miles and the tranny works like a champ. That includes drag racing every year.

The surging sounds torque convertor clutch (TCC) related but hydraulic not mechanical. A bad PCS can cause the TCC to lock/unlock causing what is known as a "chuggle" under load. Also, it may be a TCC-PWM solenoid but that can be replaced at the same time the PCS solenoid is done. Ballpark figure for each solenoid is $50.

The choice is yours depending on how much money you are willing to spend to get it fxed. Also, I know of situations where the PCS solenoid was replaced and cured the problem but the same problem returned within a year requiring eventual rebuild anyways. Everyone's situation on 4T65E trannies is unique so what works for one may not work for you but you never know. Good luck and hope you get it resolved.

My 1998 Buick LeSabre (97000 miles) is hard shifting (all gears) when the car is "hot" - same type of problem discussed by others in this forum early this year. The problem started out as an intermittent one a few months ago, but now occurs all the time. Had the fluid and filter changed and the trans checked out - got the P1811 code. The service shop said I need an entire trans rebuild. I asked why not just the PCS valve assembly, and they said that alone would not fix the problem. Althought the fluid was still red (not brown or burnt) when they changed it, they found metal particles in my filter/pan. I plan to sell the car soon and do not want to have this problem prevent me from doing so. I am willing to spend the $400-$500 to repair the PCS - but am reluctant to spend the $1500-$2000 it would take to rebuild the trans. The car is not worth much more than that. Any feedback on the risks I am taking in having the PCS done but not the rebuild will be very much appreciated.

Thanks

Leon2,

Sorry but please check the date of the thread and last post. We prefer that threads over 3 months old are not resurrected.

For your issue I would recommend posting in the proper forum (Buick LeSabre).

Thread closed.