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Customer:  Andy B.

Car:  2000 Pontiac Grand Prix GT


Andy came across a really clean Grand Prix that he took a liking to.  Only problem was the transmission was finished.   Not to be deterred by throwing a replacement transmission in, Andy picked up the car & began the hunt for a suitable tranny to go in the car.  The problem Andy began to run into was that all of the replacement 4T65’s he was finding that seemed to be in good condition were all equipped with the 3.05 final dri ve ratio…..the Grand Prix GT’s have a 3.29.  Eventually he decided that putting a more solid transmission in & then having the PCM modified for the new gear ratio was his preferred route to go, so the swap commenced.


Spectre Drop in Filter.

Although the original intent was purely to make the replacement transmission function properly with the new gear ratio,  we figured we may as well spice the car up a little bit while we were at it too.

Bone stock the car put out 158 whp, & 173 ft/lbs.  That works out to approx. 198 hp, & 216 ft/lbs at the crank.  Very respectable for the mileage the car has on it.

Datalogs showed that the car was seeing over 7 deg. of knock retard & although we didn’t have my wideband in the car, I suspect air/fuel ratios were in the high 11 range…..definitely some room for improvement here!

Tuned numbers coming soon!

Andy reports that the car’s new transmission is functioning very well now that it has been programmed properly.  Shifting is greatly improved, & fuel economy has been coming up as well.

Update Aug. 7, 2013

After several years of reliable commuting service, Andy has decided to retire his Grand Prix due to mechanical issues that he can’t justify repairing on a car with almost 400,000 kms on it.  Andy says he’ll miss her!


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