Page updated on 04-22-2018

2001 Grand Prix GT hard shift

04-06-2008, 02:31 PM
This is my first post on AF as i have been very impressed with the knowledge of the members by reading other previous posts i decided to become a member myself in hope that somebody would be able to offer me some solid advice on my current problem. I own a 2001 Grand Prix 3.8 GT with 116K and for the last 6-7 months have been having a similar complaint that many other members have posted on the site. The problem is that after the car has warmed up a while there is hard shifting and a whining noise that comes from the transmission. The hard shifting and whining noise do not occur when the car is first started or on highway driving, mostly in traffic settings after the car has warmed up for a while.

I have read many other posts stating that this is most likely a solenoid problem that needs to be replaced. I was wondering if any other users have had this replaced, how much it costed, and how effective it was in alleviating the problem. I have had my transmission fluid checked, flushed, and otherwise have taken very good care of my vehicle with synthetic oil and proper transmission tune up and such. I was wondering how difficult it is to replace the solenoid and how much I should expect to shell out. Furthermore, I had a tune up done at approximately 60,000 miles because a mechanicn falsely told me that I needed one after my catalytic converter and transmission filter were apparently faulty. Sorry for the long post, but I wanted to provide as much information as possible. I would greatly appreciate any information that would help me and if there is any other information I can provide I will be much obliged. PLEASE HELP!!!!!

04-06-2008, 09:13 PM
Welcome to AF!

It is the pressure control solenoid that is causing your issue. The part itself is relatively cheap ($20-$30), but it requires dropping the trans to access. This means it's very labor intensive and not an easy task. Probably going to run you $400'ish to get done.

04-07-2008, 08:56 AM
Typically when you get the hard shifting and whining sound a DTC has set. Commonly P1811 (Max adapt, long shift) which does not trigger a SES/CEL light. It is a Type "D" DTC. To verify you'll need a trans capable scanner or one that can read GM extended manufacturer codes. This will confirm the PCS solenoid is the cause. The reason for the hard shifting and whining is the DTC commands maximum line pressure and disables shift adapts.

I've done the PCS replacement DIY and it is not a fun job. :grinno:

In the meantime try some Seafoam or Lubegard transmission additive to possibly help alleviate the hard shifting until you get proper corrective action.

04-07-2008, 11:31 AM
Thanks for speedy response. I have a couple questions, do you know where i can get a trans capable scan done???? SES light is on, does this mean that it may not be the PCS....and if so...what else could it be??? Do i need another major tune up??? (2001 Grand Prix GT 116 k, 1 tune up done at 60K) Has anyone gotten the PCS repaired...and if so....did it alleviate the problem?

04-07-2008, 11:57 AM
If you have an Advanced or Autozone in your area take it there since the scan is free and assuming you don't want to spend any money for a diagnostics scan like at a transmission repair shop or at a GM dealer with a Tech II scan tool. Some of Autozone scanners like the Actron brand used can retrieve GM extended codes like P1XXX and whatever other codes may be present since you have informed us you have the SES/CEL light on. Best to see what those are first since engine issues will affect the autotransaxle.

My PCS replacement resolved my issue but it can be a re-occurring problem due to the poor design of the solenoid and other valve body issues as many GP members have said in the past.

04-07-2008, 08:02 PM
So I went to Autozone and had the scan done. Apparently it is a P0440 error that came up in the scan. I looked this up and this is a gross EVAP leak it could be a bad gas cap,stuck open vent solenoid and tank pressure solenoid or a evap solenoid. Do you think I should proceed to having my PCS replaced....if so where should I go??? I was wondering if anyone knew a good place in Troy, MI or the metropolitan Detroit area which was a reliable and efficient mechanic? I was also wondering if the major tune up was still needed on the vehicle in addition to this? Thanks for all your help.

04-07-2008, 08:10 PM
Here is a link below to explain the Gas Cap code. Could be as simple as the gas cap. Try a new one and have the DTC and SES light cleared or it will clear by itself after a few drive cycles once corrective action has been taken. I do not think it is related to the possible PCS issue or the cause. Try getting an estimate at AAMCO or Cottmans if available asking for PCS replacement only. They will try hard to convince you to get a rebuild though. PCS job only at AAMCO/Cottmans in my area runs around $500-$600 with the part.

04-08-2008, 01:13 AM
Excellent post on the explanation of the "dreaded GAS CAP code," thank you very much and to GMMerlin for providing the explanation in such thorough detail. The question I have, is I still fail to understand how replacing such a thing as the gas cap, would alleviate the hard shifting and the whining noise that is coming from the vehicle? Should I purchase a after market gas cap from any automotive store or should I purchase one directly from the dealer...and any estimate on the price? After further researching I found that after replacing the gas cap if the problem still does not alleviate itself will the solenoid have to be placed? I am still a little hazy as to the solution to the problem. Any advice greatly appreciated once again.

04-08-2008, 08:15 AM
To start and clarify I really don't think the evaporative emissions problem is related to the transaxle issue. Probably just a coincidence. However, it is best to get that issue resolved first. Aftermarket gas caps to include locking like the Stant brand work fine and are cheaper then the GM one. Also, make sure when you tighten your existing cap make sure you twist enough to hear the clicking sound and inspect the o-ring seal. A gas cap doesn't cost that much compared to what it will cost if you have a mechanic or the dealer do the work since you can do that yourself. If that doesn't work then you may need further diagnostics performed since evaporative emissions issues can be complex and difficult to troubleshoot.

04-08-2008, 03:00 PM
Thanks for the clarification on the gas cap issue. In regards to the transaxle issue, however, I have been doing some research on the internet, and it seems that my problem is a crack in the valve body and PCS that needs replacement. Does this seem accurate to you or is proponderous? Sorry I keep haggling, but I really want to correct the problem, the ACTUAL problem, efficiently and effectively.

04-08-2008, 06:37 PM
The PCS is a well known issue on the 4T65E autotransaxle and we covered it on AF over the years. Here is a thread from another "W" body forum that may be helpful to see why including pics. The PCS was revised but not until the 2003 model year.

Click here (

Add your comment to this topic!