Thread: Have a 4T65E Question? Please Read! Triple Edge contact info

Hey Guys Gals and Mr Trannyman We have a 2000 GTP 3800 Series 2 car. We have never had a tranny issue before with the car and in fact if we had not taken it on a highway drive I doubt my wife would have even noticed. However with me driving I quickly found out there is an issue. 1-2-3rd are all perfect, no slipping shifts solid. However if left in 4th it never gets there, and when its suppose to shift it never does, and when you lift off the throttle the revs just drop down to idle until you step on the gas and it reaches back to where 3rd gear rpms would be at. If you leave it in 3rd it will zip along fine, 75mph at 3000rpms. Lift off the throttle the rpms stay put and the car slows down. Put it back into 4th RPMS stay at 3000rpms but when you lift off now they drop to around 1000rpms until you step on the gas again they spool back up to 3000. Shifting the shifter from 3-4 and 4-3 makes no difference aside from the rpms being able to drop. The car has 137,000 miles on it, and before we owned it, it was owned by an older couple that did all Dealer Service and the car had Zero mods done to it. Only thing I have done is plugs, wires, cone filter and lube job.


I did notice when the problem happened, that the car was about 1qt low on trans fluid, below the add line, but still showing on the dipstick.

Here you go
http://www.grandprixforums.net/how-t...ess-54448.html

I belive he sold the car.

Originally Posted by BillBoost37

I belive he sold the car.

That's the easy way out. LOL

maybe I'm missing it but can you technically put a 4t65e non hd in a GTP and expect it to be reliable. I know gearing is different and it it has a harder input shaft

Originally Posted by EricGTP

maybe I'm missing it but can you technically put a 4t65e non hd in a GTP and expect it to be reliable. I know gearing is different and it it has a harder input shaft

Non HD and HD have the same input shaft. You can put one in. Many guys do top swaps on non HD trans and they can last reasonably. The biggest variable is how your foot treats the throttle.

awesome just pulled a trans from a na 01 regal. Been hearing about differential swaps. Anything I could use that would be beneficial. If I stay with this diff will I need to get an na cv shaft.

only paid about 150 for the trans so hopefully everything goes well.

A soleniod would not stop the manual linkage from moving, if I'm reading that correctly.

Fourth gear can be the splines on the clutch shaft, third could be smoked clutches or a bad sprag.

Hey Dave and Bill,
I got a built tranny for a 99 GTP (with 300m input shaft, 7/8ths chain, etc.) and the car rotted out to the point where I scrapped it, well I bought an 04 GT (L26 not L32 and NO TAPSHIFT) and was wondering what I have to change wiring wise to make it work in this car before I put it in. I have a spare transmission harness from a 99 that I can change the pins around on if I need to then put that in my 99 trans that's sitting on the table. I also noticed that the 04 doesnt have the plastic box on top for the BCM&PCM to know what gear you're in, that's intresting.

When you swap the trans instead of dealing with the wiring harness and a whole mess of other things....You can just swap the valve body, channel plate, and internal wiring harness from the 04 trans to the 99 built trans that you have.

Don't mind me asking but who built the "built trans"? And also you'll need to verify some of the valve body upgrade in the "built trans" and a few of the main ones are easy to spot like the boost valve. You can swap over most of the valve body upgrades also....all except the ones that require special reaming tools.

Previous owner of the trans said it was a TEP. when I bought it it had 10k. Then I put about another 10k on it. I just took it apart to change the 4340 out for a 300m.

On the gear ratio question. It should be posted somewhere how to program with HPT from 2.93 to 3,.29. Keep in mind that on a 2.93 HPT will show the ratio as 3.29 because it's referring to the differential not the overall ratio. 3.29 diff plus 1.121 sprockets = 2.93 overall ratio. It's basically change the ratio to 3.69 and reenter the tire size.. his auto and commit. But find that post and make sure I'm saying that properly.

On the trans swap. Lookup a writeup by me on how to put an external park neutral switch on a transmission with an internal switch for the gear selector and that will get the pcm to know what gear is selected. From there I think there might be one other pin swap that needs to happen to make it work. Check GMforums.com and a guy by the name of xtremerevolution I think is who posted it and found it on NEpontiac.org. Or look at the wiring schematics on the two years.

Looks like Xtreme had an 03, which is a different monster from this one. I though he may have gotten an 05 trans. Search on him and maybe you can find that pin stuff I'm talking about.