Bad PCS?

My 00' GT with 52k will start shifting hard intermittently. I have noticed the following characteristics:

1) It usually happens after a lot of stop and go driving.
2) Car does not buck, but does shift hard and fast with a light "thud"
3) There is a whining sound coming from the drivers side engine/tranny area
4) No trouble codes are throwing an SES light
5) After car cools down, problem disappears
6) Hard shifting occurs through all range of gears.

Is this an issue that I can drive on until Monday (its a Friday)? I will take it to an ATRA certified tranny shop early next week.

From reading, I think it's just the PCS issue that can plague the 4T65E tranny.

This stupid car, I love it to death but it seems like it has all the stereotypical issues, even with all the low miles. Oh well, I could be paying a ton more for a turtle with braces :) .

Thanks in advance,


Jesse

:iagree: PCS. I know a guy with a Buick Regal that put 80K miles on his 4T65E tranny with a bad PCS and finally had to change it. No GP owner is immune from this problem. Good luck!

Get it scanned with a trans capable scanner and DTC 1811 or 1810 will probably show.

BTW -1811 (Maximum Adapt/Long Shift) does not trigger a SES light but the code is saved for retrieval.

Yeah, that's what I figured.

20 min after I posted, I drove the car again and it was shifting longer than what it seems to before it went into its high pressure shift routine. Then 4 hours after sitting it shifted just normal.

Thanks for all your help. I'm just waiting for the Suburban to turn in front of me totaling my car now! haha

Did he go 80k WITH the hard shift problem or did the problem crop up at 80k?

That hard shifting just scared the hell out of me when it started doing it. I couldn't go that long on a bad tranny component.

I feel like I am reaping the rewards of being one of the few college students who save money...lol. At least this will be a $500-600 repair and not a $2000+ rebuild :).

Did he go 80k WITH the hard shift problem or did the problem crop up at 80k?

That hard shifting just scared the hell out of me when it started doing it. I couldn't go that long on a bad tranny component.

I feel like I am reaping the rewards of being one of the few college students who save money...lol. At least this will be a $500-600 repair and not a $2000+ rebuild :).

His problem showed up at around 80K miles and and it was finally repaired at 160K miles. The only point I see is although the 4T65E tranny can be pretty flaky it sounds quite durable too. So although the harsh shifting feels bad it probably won't destroy the tranny or drivetrain. He babied it with treatments of Sea Foam and Lubegard. When he would hear it first start singing (whining) he would pull off the road and turn the ignition off for a few minutes then restart. After that it would run fine even for weeks at a time.

On the PCS job most of us our at the mercy of either the dealer or a tranny shop. I would never recommend a PCS job DIY. To get the side cover off and to the PCS solenoid the engine and tranny has to be dropped down or tilted by dropping the subframe. Also, the driver's side axle half shaft must be removed along with a bunch of parts. So $500 -$600 is well worth it.

If this has been a known issue with this transmission over many models and years, why didn't GM just fix the component or system design so it doesn't happen?

Granted, if this issue wasn't showing up for 50-80k miles I can sympathize that engineers didn't know about this problem in the tranny design right away.

Its stuff like this that makes foreign cars owner all giddy about their Honda or Mazda that they own. Granted, they do have a reputation as more reliable cars. But you pay for that though incredibly high resale values, high market costs of new cars and higher maintenance costs with more expensive parts. One dealer when I bought my GP was trying to sell me a 98' Nissan with like 125,000 miles on it for like $9,000. My sister owns an Accord and that thing drives worse and has had more problems that my Grand Prix!

I think the Japanese auto makers are good at building small passenger cars, but still lack on the larger sedans and trucks. However, they are catching up.

Also, the owners don't realize that the c**py GM assembly plants they cite are run by the same Unions that manufacture their Honda or BMW in the US.

Anyways, sorry about the tangent :).

If this has been a known issue with this transmission over many models and years, why didn't GM just fix the component or system design so it doesn't happen?

Granted, if this issue wasn't showing up for 50-80k miles I can sympathize that engineers didn't know about this problem in the tranny design right away.

Its stuff like this that makes foreign cars owner all giddy about their Honda or Mazda that they own. Granted, they do have a reputation as more reliable cars. But you pay for that though incredibly high resale values, high market costs of new cars and higher maintenance costs with more expensive parts. One dealer when I bought my GP was trying to sell me a 98' Nissan with like 125,000 miles on it for like $9,000. My sister owns an Accord and that thing drives worse and has had more problems that my Grand Prix!

I think the Japanese auto makers are good at building small passenger cars, but still lack on the larger sedans and trucks. However, they are catching up.

Also, the owners don't realize that the c**py GM assembly plants they cite are run by the same Unions that manufacture their Honda or BMW in the US.

Anyways, sorry about the tangent :).

I can't say I disagree and know where you are coming from. The tranny situation is a sore subject for a lot GP and "W" body owners. GM supposedly resolved the issue in later model years but as usual too late. You'd figure they would design a tranny to make at least 100K miles before the first failure. However, they have represented the fact that no service is required until 100K miles.

If your car was still under warranty GM would cover the repair but once expired everyone is out there. Nothing was made retroactive or was there ever an official recall notice. Just about all possible problems with the 4T65E tranny are covered in various GM technical service bulletins. The one that is really scary is the 4th gear clutch spline stripping because they failed to use hardened splines.

On Japanese and Korean cars I wouldn't own one because they are overrated and I don't believe the crash protection is good. I've seen more foreign cars totalled out than American.

Yep, my od clutch hub was done at 70k.

I can't say I disagree and know where you are coming from. The tranny situation is a sore subject for a lot GP and "W" body owners. GM supposedly resolved the issue in later model years but as usual too late. You'd figure they would design a tranny to make at least 100K miles before the first failure. However, they have represented the fact that no service is required until 100K miles.

If your car was still under warranty GM would cover the repair but once expired everyone is out there. Nothing was made retroactive or was there ever an official recall notice. Just about all possible problems with the 4T65E tranny are covered in various GM technical service bulletins. The one that is really scary is the 4th gear clutch spline stripping because they failed to use hardened splines.

On Japanese and Korean cars I wouldn't own one because they are overrated and I don't believe the crash protection is good. I've seen more foreign cars totalled out than American.

It's too bad for GM. Most customers just want their cars to work all the time. It sad when major components have to fail. Especially when the problem could have been stopped at the design stage. But to give them some slack, the automatic transmission is not a simple piece of machinery.

As a business student and from experience, I know that when a customer has a bad product, they will tend to have a tarnished image of the whole brand itself. I find this true especially with cars. I know of several people who because of ONE problem with their Ford or other model will not ever think of buying from that brand again.

I still have faith that GM can put out a quality product. They are trying to get better, but still have a long way to go. I just hope it happens before I open the Wall Street Journal one morning to a front page story announcing the purchase of bankrupt GM by KIA or Hyundai. :eek:

I just hope it happens before I open the Wall Street Journal one morning to a front page story announcing the purchase of bankrupt GM by KIA or Hyundai. :eek:

Or worse yet......Toyota or Honda.

It's being checked out as of this morning. I took the long way hoping to warm the tranny enough to reproduce the problem..no luck.

Anyways, from recollection I was either slowing down from 45mph then applied gas or reached that speed crusing when I felt the symptoms begin. Now, could that be a torque converter issue? If I am corret from reading on here, the Torque Converter Clutch disengages around 45 mph.

Im still leaing towards the PCS, but the unifiorm speed I was decelerating from or accelerating past when issues started is possibly a sign.

It's being checked out as of this morning. I took the long way hoping to warm the tranny enough to reproduce the problem..no luck.

Anyways, from recollection I was either slowing down from 45mph then applied gas or reached that speed crusing when I felt the symptoms begin. Now, could that be a torque converter issue? If I am corret from reading on here, the Torque Converter Clutch disengages around 45 mph.

Im still leaing towards the PCS, but the unifiorm speed I was decelerating from or accelerating past when issues started is possibly a sign.

Probably still the PCS solenoid. It will exacerbate problems like making the TCC lock/unlock function look bad. There is a TCC-PWM solenoid too.

They are both located on the valve body and sit three inches away from each other on the left hand side. I'd have both solenoids replaced.

Have the shop scan for tranny DTC error codes? If P1811 shows up then it will support replacement of the PCS solenoid. TCC may also have codes.

Good luck!

Shortly after I had the fluid changed in my transmission I had a hard downshifting and slight bucking one morning as I was coming to a stop. Did this about twice and never has done it again. Now have over 305K miles on it and still shifts slick as a button. One of my friends had to have his wife's Accord transmission rebuilt to the tune of $2200 and it only had 80,000 on it. I know neither of them are hard drivers.
Do you suppose some of these issues are because of rough driving? I'm the only driver of mine and I've taken really good care of it. Now I do tend to get a little fast on the Interstates but that is not hard on them.

If the PCS is sticky it will come back. the PCS controls line pressure during shifts and at other times. You sould replace it when it acts up again. As for the Accord let me guess it was a 97-01 model year with bad bearing on the diff.

Good suggestion Troy. And we all know it is a design and quality defect. Has nothing to do with how you drive your car. It affects any GM with the 4T65E. That includes Regal, Century, Intrigue, Lumina, Bonneville, Impalas and etc. not just Grand Prix SE/GT/GTP.

BTW - When you get a bad or sticky PCS you will know it. :grinyes:

Yeah it feels like your car is being rear ended, especially on the 1-2 shift.

I finally got a call back from Certified Transmission 9 hours after taking it in. They said mechanically everythings sound (yay). But as I expected, when I asked, they told me that there was one drivetrain code in the computer: P1811.

They are going to do an electrical test, but I am almost certain they will tell me its the PCS.

Yeah it feels like your car is being rear ended, especially on the 1-2 shift.

I finally got a call back from Certified Transmission 9 hours after taking it in. They said mechanically everythings sound (yay). But as I expected, when I asked, they told me that there was one drivetrain code in the computer: P1811.

They are going to do an electrical test, but I am almost certain they will tell me its the PCS.

Yep, P1811 Maximum Adapt & Long Shift is consistent with the PCS. The reason why the whining sound occurs is because that fault code commands maximum line pressure.

It is good you are taking the appropriate steps to get it resolved. With your low mileage I believe you got it in time and there will be no further problems or internal damage. The tranny will probably last a long time thereafter.

Keep us posted of the outcome. Good luck!

I forgot what they told me exactly what was going on electrically, but it was the Pressure Control Solenoid. I will ask more specifically when I pick it up so I can let you folks know.

They are going to replace it with a new GM solenoid. He admitted they are prone to failure, but said that the aftermarket ones are junk too. Bill is going to be about $650. Sounds about right since they spent an hours labor doing electrical diagnostics and will spend 5-7 hours of labor removing the side cover off, replacing solenoid, etc.... The place I took it too seems very professional and courteous too. That's important in my book. It seems they care and want to inspect everything and get the job right rather than just dive into repairs for revenue.

This issue is fascinating, albeit expensive to fix.

The first good sign about this place you're dealing with is that they're not talking you into a full rebuild of the tranny. It seems after researching this problem, I've seen a lot of people that ended up having a shop replace the tranny or rebuild it. Some of the times rebuilding it and not replacing all the solenoids to only have the problem reappear immediately after.

If they wanted to do a full rebuild, I would have taken it for another opinion. The symptoms were too classic of the 4T65E PCS problem.

Just for everyone's info. The primary GM TSBs that cover the harsh shifting/shudder/DTC 1811 and PCS replacement on the 4T65E are:


TSB # 00-07-30-002B Issued July 2002

TSB # 02-07-30-048 Issued November 2002

Repairs complete. Total bill was $638 before taxes. $469 was the actual solenoid replacement and the rest was just parts and labor for diagnostics, fluid, filter, gasket etc...

Car shifts a little different from what I remember. I'm sure that's becuse they probably reset the computer and the PCM is relearning. Or maybe the tranny is working like it should.

Only complaint was that they lost my spare keyless entry fob. But they called me later in the day to tell me they found it. Good thing its on the way to school. Thing shifts much much smoother. You can barely notice the 2-3. 3-4 shifts and it feels better at launch.

Repairs complete. Total bill was $638 before taxes. $469 was the actual solenoid replacement and the rest was just parts and labor for diagnostics, fluid, filter, gasket etc...

Car shifts a little different from what I remember. I'm sure that's becuse they probably reset the computer and the PCM is relearning. Or maybe the tranny is working like it should.

Only complaint was that they lost my spare keyless entry fob. Their reasoning was that they didn't have it when I took the car in...right :) Oh well.

Sounds good. :bigthumb:

Normally when doing tranny work the shop will clear the TAPs info (adaptive shift) stored in the PCM. It should start feeling better after a few drive cycles and relearn. Good Luck!

Sorry to keep this going....

Why do some codes like the P1811 not bring up the SES light?

Sorry to keep this going....

Why are some codes like the P1811 not bring up the SES light?

Because it is a type "D" DTC error code, therefore does not trigger a SES light. See below:

PCM Basics & Diagnostics 101:

There are 4 types of DTC error codes by category:

Type "A" - Emissions related, turns on MIL (SES) light the first time DTC sets.

Type "B" - Emissions related, turns on MIL (SES) light if fault is active for 2 consecutive driving cycles.

Type "C" - Non-emissions related, does not turn on MIL (SES) light but may turn in SERVICE VEHICLE SOON light.

Type "D" - Non-emissions related, does not turn on MIL (SES) light or SERVICE VEHICLE SOON light.

There are two category of failures hard and intermittent.

A hard failure will cause the MIL light to turn on and remain on until the malfunction is repaired.

An intermittent failure may cause the MIL light to flicker or glow and go out (flash) about 10 seconds after the intermitent fault goes away. However, a corresponding DTC will be retained in PCM memory. If a related fault does not occur in up to 50 drive cycles (engine starts) the DTC error code will be erased from memory by the PCM.

Certain DTC error codes classified as "A" are hard and normally will not reset or cure themselves. It will require a reset after review of the error code and corrective action. However, there are certain class "A" DTC error codes after corrective action is taken and when the PCM runs the test that will erase themselves and turn off the MIL (SES) light. Evaporative emissions codes are a good example. Loose gas cap P0440 - 0442.

Codes classified as "B" may clear themselves after a predetermined drive cycle but it varies.

GM categorizes DTC codes and you need to review the Master Code or Mode 6 code listings for your specific year, model and make of vehicle. A GM service manual will contain all DTC error codes applicable to your vehicle. The code description will contain what class the DTC error code is.

I understand now. That was very helpful. Thank you bnaylor. It's a benefit to everyone have someone as knowledgeable and helpful as you posting on a regular basis.

I understand now. That was very helpful. Thank you bnaylor. It's a benefit to everyone have someone as knowledgeable and helpful as you posting on a regular basis.

You're welcome and thanks for the kind words. I enjoy passing on info that will help get a better understanding of the problems we encounter.