Hello everyone. I just got my 08 GXP which is used and only has 13K on it. I have noticed that under very hard acceleration when it transitions from first to second gear, the front end of the car actually seems to vibrate up and down. It almost feels the same as wheel hop off a start but it isn't.

My Wifes 02 GT has done this since day one and we haven't' had any other issue with it. I have full warranty and guess I'll take it in but I was hoping some experts here may have an idea as to whether it is normal or not. I was thinking that perhaps it is just too much torque/power to the tranny while it is trying to make it's shift but my wife's car is only 200hp and does this too. It feels to me like the shift is too slow and it is "grinding" or "slipping " as it transitions. I had a '99 GTP previously and it never ever did this. Especially after the PCM upgrade, it just slammed into gear.

Any thoughts would be appreciated. I have read other members with the same issue. IT really affects the drivability since you have to basically let off the gas when you know the shift is coming. I still have to try in tap shift mode to see if it is better.

thanks
Bob

Take it in.

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Six-speed top-swapped GT, sold.
2006 F-150 4x4 for a daily driver.

i thought i was having tranny issues because it seems liek it was slipping between gears. turns out the shift times were like half a second 9way too long) dropped them to .2 seconds and havent had that problem since.

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'05 WRX STi - COBB Stage 2|Invidia DP|3" Borla XR-1|Coilovers|Camber Plates|Swaybars|Endlinks|Bushings|Braces|Anti Lift Kit|DBA4000s|SS lines|
Sold: 06 Cobalt SS/SC, 99 GTP 245WHP/326 Ft-lbs, 06 R6

Seems like the fun is about to begin. I visited the dealer and they will look into my tranny studdering 1-2shift next week. I think it will be painfull to get this fixed. It happens almost everyday but it can be hard to duplicate to demonstrate. We all know how hard it is to get the dealer to address something based on what we tell them rather than them feeling it for themselves.

All I know is something isn't right and I won't accept this. I should be able to floor this thing cold or hot and have reasonable shifts. I don't care if they have to rip the tranny completely apart to fix it either. I have four years of warranty on the powertrain still so if it isn't perfect afterwards, I will just keep going back until it is.

I'll keep you all posted.

So I finally to the car in for a diagnosis and the dealer says that it is a known problem that affects some, not all GXP's. They say it is the "clutch pack" and they will order up the parts and get it taken car of. Considering I still have nearly 4 years of warranty, I will get it done and hope things go back together right.

Bob

good luck hope that fixes it for you

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i heard that the flex fuel systems also affects downshifting because it has to change the way it's distributing the fuel. or something along those lines. it causes hesitation so you dont have immediate power at WOT.

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97 GTP-Wizair, SLP headers(no cat), 1.84 RR, Ported S/C, Ported TB, Ported LIM, 3.4" pulley, 180* tstat, ZZP PCM, KYB GR2 struts
1/4-13.6 @ 102.66 MPH 2.195 60'
Stompin on ricers, one ricer at a time

Dealer changed the clutch pack but it feels exactly the same. In addition, sometimes under light-moderate throttle, I feel something which I can only explain as slipping into neutral rather into gear.

In other words, I start to accelerate and feel the car then attempt to go from first to second, but then rather than grab, it feels like it slips back to neutral for a moment and then into second as it should be.

I have to keep harassing the dealer and get this taken care of. It sucks to have a car this new and already have a tranny acting up. What is this thing gonna be like in 6 or seven years??

Bob