Transmission Questain please help

I have a 99 Grand Prix 3.8 it has 104,000 miles the transmisioon was slipping in 2nd and third so I got a used one and had it put in and just got it back yesterday from the shop.. I was driveing it tonight and it did the same thing slipping in 2nd and third where I bought the transmission they told me the trans only had 40,000 miles on it could it be something else (computer) or do you think I got a bad transmission?? Please any suggestions would be great...

Have you had it scanned for trans codes(CEL on) ? The chance that two different transmissions would do the exact same thing is highly unlikely.

On the first tranny I did have it scanned I cant remember the code but I know it meant there was a slipage in the transmission I had two different shops at that time tell me it needed to be replaced......

I went to the tranny shop they said it was the same code as before 1811 they asked me if they cleared the codes out after putting in the new tranny I called the place that did it and they said they replaced the battery so that should have cleared the code... Would the computer hold the code even tho the battery was taken out? And if so would that be the problem that the code was left in the computer making my new trans do that?

Disconnect the battery negative cable overnight and then see what it does the next day. The P1811 (Long Shift, Max Adapt) DTC is normally a flaky Pressure Control Solenoid (PCS). Possible the second tranny had a flaky one since it is a common problem on a 4T65E autotransaxle. The tranny shop should have reset the PCM module and cleared the old tranny adaptive shift data which is stored after the PCM module relearns. It should be cleared whenever a replacement tranny is installed or major trans work is done.

P1811 does not always mean replace transmission. Like Bob said its a bad PCS 99% of the time. What year car did you get your replacement trans from? With that code stored the trans should be in hi line pressure mode which would make it shift hard and possibly whine.


Troy

it came from another 99 grand prix, I called the place where I got it from they told me that it may be the computer since it doesnt do it all the time just every so often does that make sence?.. Happens when I have been driving it for a while. I did tho drive it with the old trans about 600 miles over Thanksgiving and it didnt do it once till I got back to town and a week later right before I took it in to get the other one in it started doing it again so its not a constent hard shift, I felt it last night and didnt feel it at all today. So Im thinking the old one probably is not bad?.. I had the computer reset this morning so I guess I will have to see how it goes from here.. Any more suggestions would be great. Also would that old code be stored if the battery was taken out and the computer not reset??...Thanks a Million, Mike

With a bad PCS it won't always shift hard. You need to find a good shop that knows how to work with the DTC P1811. Or you can just shell out $500 and get a new one. Also doing the PWM TCC solenoid won't hurt either. If you let the computer set over night its possilbe that the shift adapts got resest but once it learns them again it will probably get rough again. How many miles on your car sense the tranny swap, and did the shop clear the old codes?

I have MAYBE 50 miles on after the swap. Yes I had the codes reset today on my way home tonight it started to do the hard shift. I bought it from www.cherry-auto.com (http://www.cherry-auto.com) they say it has a 90day warranty on it with labor but I called them today and they are trying to convince me its a computer problem and not a tranny problem since the tranny has only 40,000 miles on it. It is doing the exact same thing that my old tranny was doing..

I have been trying to find someone who can work with this code at a decent price everyone wants over a 1000 dollars. Last night I was driveing it and it was running fine then it started the hard shifting again as normal, then I stopped at a stop sign went to take off and was going into 2nd and it didnt want to go at all the whole car was shaking finally would go into third I would go to give it gas to go a little faster to get home I push on the gas and it would shake even worse, thought the tranny was going to fall off, any ideas? would this have to do with the PCS? or have you heard or would this be something else?

does this trans have a modulator can on the front of trans????
there may be a line pressure problem caused by this
contact me directly,,I don't read all posts
[email protected]

does this trans have a modulator can on the front of trans???? there may be a line pressure problem caused by this
contact me directly

No it does not. The 4T65E autotransaxle does not have a vacuum modulator. Line pressure is controlled by the PCM module.