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Transmission Shifting Hard After Swap

walkure

walkure

New member
My GT trans gave up and I swapped in a spare trans from a GTP. After this swap I copied over the stock trans tables from the GTP and also calibrated the speedometer. On the test drive the trans slams into each gear and shakes the whole car. Is there something that I missed or is the spare trans also done for?
 


WarStryker13:
I did change the TC to the larger GTP one because I think that is what failed.

Scottydoggs:
I am using HP tuners. It is Changing the drive sprocket ratio.
 
Here's the settings from my GTP:

Trans_zpszhx4kjfa.jpg
 


Pretty damn sure. I have the donor car sitting behind the shop.

I'll have to dig out a gauge and check the line pressure tonight.
 


ok, i had no idea how you came to own it. cause the wrong tranny or with the wrong tuning will also make it shift hard and then they eat them selves from it.
 
The diffs are the same right? I swapped to 3.69 gears and over kill forgot to change the diff setting as I also swapped the diff, it hard shifted till it was corrected
 
Last edited:
I'm hoping that it is just a shift adaptation issue. But I am going to check the PCS. When I drained the fluid it looked old and neglected which leads me to consider a solenoid issue. I'm just trying to put a bandaid on the car till I can save up for a TEP trans.
 


The issue is you did it in HPT. HPT doesn't show you all the tables and you are missing things. You really need DHP to copy the entire trans over and then it would be happy.

Right now..it's pissy because of tables you can't see.
 
Well I'm stumped. Found out today that if you want to check trans pressure and have headers installed you are SOL. I'm going to see my local 3800 yoda tomorrow night and see what he can do.
 
this thread came from using dhp bin to hp, i did some other stuff hp cant do, emailed him the bin file and running off it now. http://www.grandprixforums.net/threads/102530-Change-Vin-Serial-Number-of-Bin-File

if it comes to it, i can make a na bin with the gtp tranny in dhp with the same osid # as your bin, then you need to follow that link i posted and change the vin # in the bin file so HPT will like it.

if you have the old version of hp it will open and read, then flash the dhp bin file. as long as the osid and the vin match.
 
Well Bill was right. I took the car to a friend and he made one change using DHP and the car now runs perfect.
 
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