Does anyone have a writeup on replacing a pressure control solenoid?

[ritter875]

I recently took my 2000 Grand Prix GT to a transmission specialist and had them read the codes after getting hard shifts occasionally in traffic. On the highway it seems fine. I suspected the problem was the PCS before taking it to the shop after researching it on here. When you shut the car off the problem corrects itself temporarily. The same problem matches a number of other threads I have looked at. Sure enough the codes read the the pressure control solenoid is bad. If anyone has a step by step write up for changing it I would greatly appreciate the help.

Thanks.

[BNaylor]

IMO you are better off letting a shop do the work but it is your choice. Here is a general procedure applicable to all GM vehicles with the 4T65E autotransaxle.

Disconnect the battery ground (negative) cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Starting and Charging.
Remove the throttle body air inlet duct. Refer to Air Cleaner Intake Duct Replacement in Powertrain Management.
Install the engine support fixture. Refer to Engine Support Fixture.
Remove the front engine mounts. Refer to Engine Mount Strut Replacement in Engine.
Raise and support the vehicle. Refer to Vehicle Lifting.
Remove the left front wheel. Refer to Tire and Wheel Removal and Installation in Steering and Suspension.
Remove the left engine splash shield. Refer to Splash Shield Replacement - Engine in Body and Frame.
Remove the stabilizer shaft links from the lower control arms. Refer to Stabilizer Shaft Link Replacement in Steering and Suspension.
Remove the left tie rod end from the steering knuckle. Refer to Steering Knuckle Replacement in Steering and Suspension.
Remove the wheel speed sensor harness connector. Refer Wheel Speed Sensor Jumper Harness Replacement (Front) in Brakes and Traction Control.
Remove the left lower ball joint from the left steering knuckle. Refer to Steering Knuckle Replacement in Steering and Suspension.
Disconnect the left drive axle from the transaxle. Refer to Wheel Drive Shafts Replacement (Left) or Wheel Drive Shafts Replacement (Right).
Secure the drive axle to the steering knuckle/strut. Caution: Failure to disconnect the intermediate shaft from the rack and pinion stub shaft can result in damage to the steering gear and/or damage to the intermediate shaft. This damage may cause loss of steering control which could result in personal injury.
Remove the pinch bolt at the intermediate steering shaft. Refer to intermediate Steering Shaft Replacement in Steering and Suspension.
Remove the intermediate shaft from the steering gear. Refer to Intermediate Steering Shaft Replacement in Steering and Suspension.
Disconnect the three-way catalytic converter pipe to the right (rear) exhaust manifold. Refer to Catalytic Converter Replacement in Powertrain Management.
Support the right side of the frame with jackstands.
Support the left side of the frame with jackstands.
Remove the transaxle mount bracket. Refer to Automatic Transmission Mount Bracket Replacement.
Remove the transaxle mount. Refer to Automatic Transmission Mount Replacement.
Loosen the engine mount lower nuts. Refer to Engine Mount Replacement (Front) and Engine Mount Replacement (Rear) in Engine.
Loosen the right side frame to body bolts. Refer to Frame Repair in Frame and Underbody.
Remove the left side frame to body bolts. Refer to Frame Repair in Frame and Underbody.
Adjust the jackstand to the lower left side of the frame.
Position the drain pan under the transaxle.
Remove the wiring harness connector.
Remove the case side cover bolts.
Locate pressure control solenoid (PCS) on valvebody. See pic.
Remove PCS electrical connector and retaining bolts.
Replace PCS.

Reverse above for reassembly.

Note: Be sure to replace the side cover channel gaskets during reassembly.

EPC- Pressure Control Solenoid (PCS)

[ritter875]

Thanks for the help. I'm not sure which route I'll take. The estimate from the garage was about $900 to have it fixed and they said that didn't guarantee anything. I have been told the same problem is likely to happen again in a year or two especially with higher mileage cars. Mine has 104,000 on it. They recommended replacing the transmission. I was thinking I would replace the PCS with the help of a few neighbors who have a pit to work from and between us, the majority of the tools we'll need to get me by until I'm ready to trade up on another one.

Again, I appreciate the help. I'll keep you posted on how it goes.

[BNaylor]

What shop is this? AAMCO charges around $600 with part in my area and will do just the PCS solenoid exchange but will limit their warranty as a result.

Be sure to replace the side cover channel gaskets or you may get ATF coming out of the overflow/relief valve after the job is done. Good luck!

[ritter875]

The garage I took it to was local. It's called Pro-Trans located in State College, PA. The estimate was a little under $900 for a new PCS and around $1900 for a rebuilt transmission. I'll probably put this off for a couple weeks until I'm sure I have the time on a weekend to get it done, or I might look elsewhere for a garage that can do the work cheaper.

[BNaylor]

Also, if you haven't already check out the following thread in its entirety. No guarantee it will work but it could and definitely a cheaper route to go in the interim and a DIY job.

Click here

[ritter875]

Wow......that looks like it might work for me as well. I will surely give it a shot before I try replacing the PCS. If it fails I'm out 60 bucks, that's pretty minute considering they want $900 at the garage to do the job. They tried talking me into replacing the whole transmission as well. I tried the seafoam solution in a can with no avail roughly a month ago. I didn't know it could be so damaging. Instructions and the advance auto rep. said I could just leave it in there. I'll probably give it a shot tomorrow. Thanks!

[ritter875]

Again thanks for the help.

What brand of shift kit do you recommend I purchase for my Grand Prix and where can I find it? Do you have a link to purchasing one online?

[BNaylor]

ZZP

Thrasher

Good luck!

[ritter875]

I think I'm going to go with the kit from Thrasher. It has been my experience that you get what you pay for and judging from the research I've done it falls among the middle/upper class price range for kits like this.

All kits make line pressure higher though. While I don't know a lot about transmission work, I understand the PCS giving me rough shifts is commanding full line pressure. That's why I get the jerk I do from time to time when it acts up in traffic. I know you have had good results with them, but out of curiosity how does the kit work to correct this problem?

Thanks!

[BNaylor]

Originally Posted by ritter875

but out of curiosity how does the kit work to correct this problem? Thanks!

By helping to keep the 1-2, 2-3 shift timing low or below .65 seconds. When the P1811 (max adapt, long shift) DTC sets the PCM sees an issue and commands high line pressure causing the harsh upshifts.


The advantage of the Thrasher kit is it comes with more rebuild parts like new accumulator springs and the accumulator housing gasket so the cost is relative.

[ritter875]

I went with the kit from ZZP after Thrasher did not respond to my requests. I was surprised that the kit consisted of simple plastic spacers and no springs. The installation on a concrete garage floor was not fun, but the kit is in. I followed the instructions provided by ZZP to a T.

Still I worry about something falling apart in there after I reinstalled the pan. And on hard acceleration I get slipping now. Could it be because of the mileage? My tranny fluid was dark red/almost black. But there were no metal shavings to speak of.

I'm hoping the new problem goes away as the transmission fluid works itself completely through. So far I've only driven it 10 miles or so. Until then I'll avoid the hard acceleration and hope for the best.

[BNaylor]

Originally Posted by ritter875

Could it be because of the mileage?

104K miles is really not that high. I've done the mod on GM cars with over 200K miles and the original autotransaxle. You may have another internal issue in the tranny causing the slipping but best to run it for awhile and see what happens.

What brand and type (Dex III or VI) ATF did you decide to use?

[ritter875]

I'm running Dextron III in it for now with the intention of dropping the pan again in a month or so and replacing it with the good stuff to get some more gunk out of there. Would a high mileage transmission fluid formula help my cause at all? Thanks!

[tblake]

I would almost wonder if you have fluid leakage causing the new slipping problem. I know you probably wouldn't want to go back in there, servicing transaxels on the ground with jackstands is never fun or easy, but I think if it were mine I would have another go. If I remember right, there is a paper gasket in there, and the bolts should be tightened from the center outwards much like a head gasket.

I have 135,000 miles on my trans, changed the fluid at 80k, and it shifts like it did when it rolled off the assembly line. Although I tend to be very easy on it cause I know the 3800 could rip it apart (especially the 4th clutch shaft).