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Getting ready to take my GP back to the tranny shop.

Dohner

Dohner

New member
It is pulsing in 3rd pretty bad is there anything i should suggest that they look at to try to cut down on some Diagnostic time. The RPMS will drop about 2to300 RPMs but it only happens at about 1/4 throttle let off a bit or give it a little more gas comes right out of it and it dosent do it all the time.
 


Sounds like a TCC problem and I can about guess that they dont upgrade the TCC valve during a rebuild and the stock ones are very common to wear and cause odd behavior. Let them do a road test to verify the condition and see what the suggest, and it BETTER not be a blame on the pcm because that is not the problem! Sorry to hear you are having problems and I hope they get you fixed up ok. One thing you may even try before taking the car in..... There is a vacuum modulator on the front of the trans and they should have replaced it with an aftermarket one during the rebuild and if the did it will be rather small and gold in color. There is an adjustment screw just inside behind where the vac line attaches and this will slightly alter line pressure. You can use a pocket flat blade screwdriver and turn it in one or two turns and see if this helps out. If you have a larger "gray" colored modulator then it is the original one and is not adjustable.
 
Thanks for the input. Which way would i turn the screw if i have the after market one. Where are you at in Ft. Wayne if they tell me some stuff that i am not sure about i might have to stop by and see what you think about it or say. And maybe you could also point me in the right direction to getting it taken care of.
 
Me and the Orginal poster have the same year car. a 2002 gt and there is no vacuum modulator on my transmission. And my rpo codes tell me that its the 65e Non hd with the 3.29 chain set. Tranny Please Double check about what you said. Not trying to be a **** but the 65e's in the 02's have no vacuum modulator..
 
19SE92 said:
Me and the Orginal poster have the same year car. a 2002 gt and there is no vacuum modulator on my transmission. And my rpo codes tell me that its the 65e Non hd with the 3.29 chain set. Tranny Please Double check about what you said. Not trying to be a **** but the 65e's in the 02's have no vacuum modulator..
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I will caution you only this one time. Be very careful questioning the expertise of not only one of our site sponsors but also a gentleman that has many years experience in working on transmissions. If you differ with someone with such experience you would be wise to post proof of your contradiction.

I hope that your re-visit to our community is not a repeat of your last time with us.
 
He is correct that 02 does NOT have a modulator. This is the "4T60/E" section, not the 4T65E section. I dont have time to ask everyone what make/model/year there car is and it is not my responsibility to post in the correct section. Keep in mind that just because people post in this section does not mean that the year of car in the sig is what car is in question.
 


I just went through a rebuild of my 02's trans. The warranty section of the lot sent it to aamco. I've had good luck with it so far.
 
Hey guys sorry I didnt even notice the section difference i didnt want to start anything but thanks for informing me that i dont have a vaccum on this tranny i was looking for a good half hour the other day. THanks for all your guys input. Sorry again. Hope there is no hard feelings here.
 
No worries, I really think there should be a 97+ section for the newer bodied prixs (97 GT still 4T60E) to keep it easier to follow and post in the correct section. Did you have a chance to get the car back to them to inspect yet? Now that I know it is a 4T65E my above advice doesnt directly relate to your problem. Some pcm tuning my help cover up the problem and I have had to do this on a few stock transmissions in the past with modded engines to get rid of the tcc cycling up and down but the real problem is typically in the valve body.
 
I take the car tomorrow which is the 17th and hopefully they tell me good news like they will put another tranny in it for free. It has not been acting up as much latley so i dont know. They will probally tell me nothing wrong with it cant find anything. That would piss me off. I will let you all know what i come up with . THanks
 


Hey just to let you know the tranny shop said they couldnt find anything wrong with it. THe guy was really thurow as far as i could tell. He said he reset all the pressure something's in it and none of those were reading abnormal or anything. So he said as he can tell its good to go. I know something was wrong but now that he reset all the pressure things it hasnt done it since. Tranny man do you know what he was talking about with the reseting the pressure things. I know they have a name but i cant remember what he called them.
 
They likely reset the Adaptive Shifts in the pcm with their scan tool and basically this will put the pcm back at a starting point and will relearn to the trans the more you drive it. This generally will clean up issues if there are any and works good for a few weeks and then may return to how it was but Im sure they gave it a good drive and are confident that it is ok so you should be fine.
 
A friend with a 2000 gtp was having a problem like yours and he changed from his over kill pcm back to stock and it fixed it. I'd lean towards a bad pcm.
 
19SE92 said:
A friend with a 2000 gtp was having a problem like yours and he changed from his over kill pcm back to stock and it fixed it. I'd lean towards a bad pcm.
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I didnt see in this post were he was using an aftermarket PCM, and I have never heard of a stock PCM changing only tranny settings while everything else works fine, so I would tend to think its not the PCM.

There is an enherent problem with GP's and the RPM fluctuating 400 to 600 or so RPM's usually when at part throttle and going up some sort of incline. I own 3 GP's and 2 of them have done this in the past. I would have to agree that the trans shop did the right thing by reseting the adaptive shift in the PCM. I know when I had my trans refreshed, I was really pissed because I had never had this issue, then all the sudden it started showing up. I tried to change a few setting and no change, so I reflashed the PCM (which will also reset the adaptive shift as well as LTFT's) and have not had the problem since.

webracin
 


Hey just an update still no issues since i took it back to the tranny shop and they reset the Adaptive shift in the PCM. I am happy i was hoping i wouldnt have an issue a few weeks down the road and i havent its been about 2 months now so i think i should be in the clear.
 
Would resetting the adapts in effect flash the PCM? I was just wondering in the case of an aftermarket PCM if doing this would erase the settings and go back to stock?
 
Resetting the adative shifts will put the pcm back at a base starting point. This will not change any of the hard settings in the tune, but puts the pcm at a base starting point as it will watch shift timing and adapt to this over time. Often even when reprogramming a pcm this is not changed and can cause a car to have poor or sloppy shifts until the pcm learns to the new trans.
 
I'm having a similar issue with my 1999 GTP. Everything is stock on this car at the moment. The problem started manifesting itself after I had one of the little plastic heater core elbows blow out. My alternator shorted out during this and had to be replaced. I'm wondering if this scrambled something in the PCM. My RPMs bounce about when the tranny hits third and the RPMs drop to between 1500 and 2500. Anything above or below that is not an issue. I know this tranny was rebuilt at 160K and currently my car is at 226K. I was planning on taking it in to have it flushed since I don't have a record of when that was last done. Will they reset the adaptive shift during that process or will I need to ask to have it done.
 
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