2002 GP GT Hard shifting

[bronzemist02]

Recently my 2002 GT has been shifting pretty hard. I first noticed a few hard shifts when shifting from 2nd to 3rd before christmas. I got the transmission fluid and filter changed last week and the problem seemed to all but go away. Today when I was driving it the shifts from 2nd to 3rd and 3rd to forth were really hard (you could feel the tranny engage gear). The car seemed to only shift into 4th once or twice and didn't seem to shift when i decelerated and returned to about 95km/hr.

From what I have read in other threads there should be a code thrown if the transmission goes to max pressure causing a hard shift. I am thinking of taking it to check for codes and then take it to a local transmission shop to have the pan looked at for shavings and such.

Any suggestions on what could be done to fix this problem? I found a used transmission for 500 from the same year grand prix, but it has about 3000 kms more than mine and could have the same problems. Thanks.

[bronzemist02]

Anyone?? I have some lucas transmission restore that I'm thinking of putting in later today. Seemed to help on last cars I drove.

[jbamonte]

You may want to take a look at the thread on the front tranny page-"4T65E Hard Shift-Solution" where I described my issue-Same tranny has the GT. It might help if there is nothing else wrong with your transmission!

[bronzemist02]

Ok. Thanks. Getting car checked out tomorrow hopefully.

[rolyat]

You might try looking into some stuff called cermax. I put some in my tranny that had intermittent hard shifts and horrible tcc shudder, and within 50 miles it felt like a brand new transmission. kind of expensive at $40 a pop, but it helped mine.

[bronzemist02]

Ok. That seems to be very similar to the Lucas product I have here. It is supposed to lubricate moving parts and stop wear as well. It is also about $20 cheaper. :P

Did you know that a transmission from a 2000-2003 monte carlo ss is the exact same ratios as a 1997-2003 grand prix se or gt 3.8 n/a tranny? Thought it was interesting.

[rolyat]

nope, I didn't know that, sounds logical though.
Yeah, I put about 3/4 of a bottle of that lucas in mine and it seemed to help but not like I was hoping. So i got the cermax and it just made the shudder and shifting problem dissapear! That stuff really is in a class of its own. My dad got some cermax for a 95 chevy 1500 that had an engine knock and after 20 minutes of driving we pulled up to a stop light and it literally felt like it had died because it was running so smooth and quiet, we had to check the tach lol. I hope the lucas works for you, but if not cermax is a good last resort.

[bronzemist02]

I tried the lucas. Still shifts hard when it is warmed up. Going to take it to a local transmission shop soon and get it checked out for free and get solenoid fixed or just install a shift kit. There is one on zzperformance for about $30 just have to get it put on.

[rolyat]

Have you had it checked by the transmission shop yet?

[bronzemist02]

No. Haven't taken it to shop yet. I got a referral to a shop about 45 mins away from my house. Might go tomorrow, but want to have something else to do there too though so I'm not driving there and right back home.

[Ibwrong]

Dumb question thought. The additives pretty much just mask the real problem at hand right? Im not trying to be a dick just wondering..

[rolyat]

Yeah I understand that, gas isn't getting any cheaper lol.

[rolyat]

Dumb question thought. The additives pretty much just mask the real problem at hand right? Im not trying to be a dick just wondering..

That just depends. Some additives might but others can truley help. The cermax stuff I used in my tranny definintely did more than mask a problem, I really think it fixed it and probably added some life to it. My tcc shudder was HORRIBLE and seemed beyond repair but that stuff eliminated it. My issue was probably a fluid pressure problem in the valve body. As long as something isn't mechanically broken or electronically screwed, that stuff can work wonders

[gtpinsc]

ever heard the saying " do they sell p*ssy in a can"? well they dont sell mechanics in a can either... additives will just hide the problem for a lil while. get it scanned i bet u have a bad pressure control solenoid.

[bronzemist02]

I'm going to get it scanned. Hopefully for free.

[gtpinsc]

any "decent" shop will scan for free.

[bronzemist02]

Took the car in and got the pressure control solenoid and some valvebody pieces replaced. Was $325 before tax ($375 incl. tax). Pressure solenoid line pressure setting was set a bit higher to give a bit firmer shift and help compensate some if it starts to go again. Is shifting very well now.

[rolyat]

Took the car in and got the pressure control solenoid and some valvebody pieces replaced. Was $325 before tax ($375 incl. tax). Pressure solenoid line pressure setting was set a bit higher to give a bit firmer shift and help compensate some if it starts to go again. Is shifting very well now.

That's good to hear. Was the solenoid bad or did you replace it just to be safe?

[gtpinsc]

pressure control solenoids are a common problem... the p1811 code is 99.99999 percent a bad pressure control solenoid...

[bronzemist02]

That's good to hear. Was the solenoid bad or did you replace it just to be safe?

The solenoid was bad. It was maxing out the transmission line pressure reading and was making the car pull pretty bad when it was warmed up. Didn't do it when I got the transmission shop owner to take it for a drive tho. lol. Was replaced along with valve body seals and is working great now. Solenoid was adjusted some for line pressure tho so it is set to shift a bit firmer than stock now.