Grand Prix GTP transmission problem

[gtp4life]

I have a 1998 Grand Prix GTP that I just recently bought off of a private seller while driving the car I noticed that the transmission shifts perfectly fine into 2nd, but winds really far until about 47mph at the end of 2nd then shifts hard into 3rd. When driving normal 2nd winds at about 3200rpms then while trying to shift into 3rd.
I also noticed at WOT from a dead stop it shifts fine into 2nd, but at the end of 2nd at 95mph it won't shift into 3rd. The tack needle just bounces sort of like the transmissions not telling the car to shift out of 2nd an into 3rd. Some people that I have spoken to about this have said that it could possibly be the transmission solenoid? I was wondering if someone could help me out here? If you have any ideas of what could be wrong or any suggestions please let me know I would greatly appreciate it. Thanks for your time an all your help.

[gtp4life]

I forgot to mention that the car has 170,000 miles on it.

[CrazyHorst]

You can go 95mph in 2nd gear?

The shift-solenoids have something to do with the problem but not all of it...there are other components which have to "do as commanded".

Personally...after 170k I think I'd weigh out a reman 4T65E. Get one with a warranty and you'd be good to go for a long time.

The hard shifting isn't necessarily bad for anything. But if clutch packs are fighting each other that will shorten the life.

Another possibility is there is crud built up somewhere in the valve body which is causing a fluid restriction and hence a delay in one of the fluid-logic functions. It is possible that a fluid change and or something like SeaFoam could help but beware of the low-buck trans flush...in my experience they've led to more transmission changes than any other problems.

[tblake]

First thing I would do is bring it to a trans shop and have it scanned for trans codes. More often than not, trans DTC's will not illuminate the ses light. If a code is stored it should point you in the right direction of what solonoid is bad.

[gtp4life]

Thx guys for the info Ill take my car to the shop this weekend to see if any trans codes show up.

[tblake]

Copy, good luck! Report back!

[gtp4life]

OHH another question I have since im on the subject of transmissions Lol! Do the GTP's from 97-03 have the 4t65e HD trannys or just 4t65e's?

[tblake]

I think 97's have the 4t60e, some 98's have a 4t60e and some have a 4t65e, and I think all 99-03's have 4t65e. All GTP's with a 4t65e have the HD differential.