4T65E Trans Shift Hard, P1811 DTC

[BNaylor]

Originally Posted by BuickRegal1

One question, where is the PCS and why can I not change it also when i take the pan off?

See pic below.




EPC- Pressure Control Solenoid (PCS)

[Floopy]

BNaylor:

I have a 1999 Buick Regal LS, with the shifting problem that is the focus of this thread. I have had this problem for years (hard shifting, engine whining coincident with engine RPM). I wanted to try the shift kit mod you mentioned, as it seems this is a consistently successful fix for this problem. I was going to treat the transmission fluid with the seafoam TransTune treatment, followed by installing the shift kit mod during the fluid replacement. Do you recommend one shift kit over another? I thought the ZZ Performance kit did not include a new set of valve springs; is that something I should consider when choosing one kit over another?

[BNaylor]

Originally Posted by Floopy

BNaylor:

I have a 1999 Buick Regal LS, with the shifting problem that is the focus of this thread. I have had this problem for years (hard shifting, engine whining coincident with engine RPM). I wanted to try the shift kit mod you mentioned, as it seems this is a consistently successful fix for this problem. I was going to treat the transmission fluid with the seafoam TransTune treatment, followed by installing the shift kit mod during the fluid replacement. Do you recommend one shift kit over another? I thought the ZZ Performance kit did not include a new set of valve springs; is that something I should consider when choosing one kit over another?

Did you ever get it scanned for the P1811 (Max adapt, long shift) DTC? In many cases the shift kit works but not all depending on how bad the PCS solenoid is or other internal issues. But for the cost it doesn't hurt to try it. Any shift kit is fine. The ZZP kit works but does not have all accumulator parts. But if you want the accumulator springs replaced try the Thrasher or Trans Go kits. I have the Thrasher in my '97 GTP and ZZP in the '99 Regal LS. For tranny fluid using the Dexron VI which is downward compatible with Dexron III.

Good luck!

[XSaaber]

My 2003 Impala had thrown P1811 code and occasionally had a hard 1st - 2nd shift. I went to a transmission shop and had them change the fluid and filter, plus check whatever else out. They had two possible causes the PCS or the input clutch piston seal. GM used a short lip seal which apparently wears out. The PCS job wa $500 and the seal was a rebuild which was well over a $1000. I went with the transgo shift kit, installed it and the hard shifts haven't gone away altogether but they are greatly reduced; only two in the past few months. I never noticed the 'pump whine' so am a little confused by that.

If I could find a car with a bad transmission cheap or a used cheap transmission, I might buy it for the adventure of rebuilding it myself.

[BNaylor]

Originally Posted by XSaaber

I never noticed the 'pump whine' so am a little confused by that.

Not all PCS issues cause a pump whine. About 50% who get a P1811 DTC may get it. If you get a whining sound it is because the PCM module commands maximum line pressure after seeing a fault. Shutting the engine off or clearing the P1811 DTC will normally cause the noise to go away until it kicks in again.

Another way to reduce the possibility of the P1811 DTC and harsh upshifting is use manual shifting versus automatic especially in town driving. But this is only a temporary work around.

[Milanz]

Originally Posted by RED REGAL

Good morning its Sunday and I installed the shift kit yesterday.everything went smoothly but its a messy job,hint don`t take the accumulator apart on the kitchen table you will get yelled at!The car shifts excellent from 1st to 2nd,2nd to 3rd also great but overdrive is still jumping.I know the kit doesn`t claim to fix overdrive problem,but I was hoping.When I took car on to the hiway and held the pedal down car shifted great but when engine got over 4000rpm it started missing and backfiring thru intake also check engine started flashing then light went off.I suspect maybe bad gas I`am going put some gasoline antifreeze maybe water in the gas.any suggestions appreciated!

I started getting the shifting problems 2 years ago on a 2002 Impala 3.8 and the dreaded code P1811. A new PCS by Mr Transmission for $500 solved everything....smooth shifting again and no cluncking or hard shifts.

Last few weeks noticed poor shifting and poor power. When I floored the gas pedal the transmission downshifted and the revs went to 5000rpm but no acceleration and the engine started misfiring and check engine light flashed a few times. On easing off on the gas the transmission upshifted with a harsh clunk and the flashing check engine light went off. Only way to accelerate on the highway was slowly with part throttle. I scanned the codes and got P1811 again and P0300, P0301 (Misfire and plug 1 misfire). Took car to Mr Transmission who checked out the transmission and said all was fine with shift points and timing but suggested it could be a plugged catalytic convertor as he has seen that before many times. If you google for "plugged GM catalytic converter" you'll find it is a huge problem with symptoms exactly as I described.
A trip to a muffler shop (Speedy) and they disconected the cat and tested the vehicle....perfect power and super smooth shifting again. They installed a new cat and all is perfect again without any engine codes. The Impala has full power and nice smooth and quick shifting.

Get your codes scanned. You might well have a PCS transmission problem but it could also be a plugged cat. Any good muffler place will test your cat.
Sorry for the long post.

[Tkingman1]

Hi there. I'm glad I found this thread.

I have a 2002 Pont Grand Prix GT 3.8V6 (122K miles) with the hard shift symptoms and code p1811. Started in Jan. went away for awhile and then came back last week. Shifts fine when cold but once hot (i.e. after hiway drive) then the hard shifts start. Also have noticed the pump whine (even before problem but thought that was a "pontiac thing").

One symtom I have not read in these posts is a "burning oil" smell as my wife calls it. I said it smells more like burning brakes (or maybe clutch plates or trans fluid?). I'm just wondering if others have experienced this smell or could I be looking at something more than the trans shift kit/pcs repair?

I'm hoping to avoid a complete re-build cost. Would be great to keep repairs under $1000 and hopefully get another couple years out of car. But then again "s__t happens" and you have to deal with it.

Thanks.

[BlueRiff]

Hi All,

A lot of great info here! Will this solution work for an MD7 variant of the transmission. Mine was manufactured in China. Thanks heaps!

[BNaylor]

Originally Posted by BlueRiff

Hi All,

A lot of great info here! Will this solution work for an MD7 variant of the transmission. Mine was manufactured in China. Thanks heaps!

Welcome to AF.

What year make/model car?

[BlueRiff]

Originally Posted by BNaylor

Welcome to AF.

What year make/model car?

Hi BNaylor,

Thanks for the prompt response. I am in the Philippines, GM China released here a re-badged version of the 2004/05 Buick Regal as Chevrolet Lumina. Mine has the LB8 engine 2.5l V6 SFI. I heard it's a derivative of the LG8 with lower displacement. I looked at the parts code in the trunk cover and saw 4T65E MD7 as the transmission code. I usually drive late at night or early in the morning. I don't usually get the symptom unless it's a stop and go traffic for about 40 mins or so. You mentioned it's about the repeated cycles of upshift, will that mean it's ok to drive it to a highway and mostly stay in 4th gear? The city driving is what makes the shift cycles happen so often. Let me know if there's any other info I need to pull-up.

Thanks,

[fullfactory]

I know this is an old thread, but I've got the same problem and I want to ask a few questions (Hoping you are still out there).

I wanted to know how things are going with your Venture. Still have the vehicle? Still working well (shifting problem still solved)? Scale of 1 to 10 - How difficult were the repairs you completed? (10 being really difficult)

Thanks in advanced for you response...

[fullfactory]

To kgstrap,

Sorry for the Re-Post (forgot to address it)

I know this is an old thread, but I've got the same problem and I want to ask a few questions (Hoping you are still out there).

I wanted to know how things are going with your Venture. Still have the vehicle? Still working well (shifting problem still solved)? Scale of 1 to 10 - How difficult were the repairs you completed? (10 being really difficult)

Thanks in advanced for you response...

[trannyman52]

when accumulator is apart,,,the bores should be scuffed ,,,,polished with scotch-brite to assure a good seal,,,,,possibly replace seal rings on pistons also gbaum

[fullfactory]

trannyman52

Are there any photos/diagrams available, that you've seen, in "internet-land" to show the installation of a shift kit? Photos/diagrams of the Accumulator?

Are you familar with this shifting issue in this thread? In your experience, will this fix help with the shifting problem? Are there any short term or long term problems associated with this repair?

Thanks again for your help....

[trannyman52]

the pics on this post are very good,,on what to expect when taking apart,,other than usually the springs are broken!!!... Usually just replacing the springs,scuffing the bores with scotch-brite,,,replace the rubber piston seals,,,,....should work like a million bucks!!!!

There is no down-side to this repair,,,you are only bringing the servos back to factory spec

There are other issues with the valve body,,,but are more related to rebuilding the trans due to the fact the VB is not too acessable without the trans out of the car

gbaum