4T65E transmission experience needed here, please!
I own a 2002 Grand Prix with the L36 engine and 4T65E trans. I am the only driver of the car which I have owned since new, the mileage is at 241,000. I have never replaced the transmission fluid. This GP is a daily driver, gets very little downtime, and in recent years, I have put on around 25,000 miles or more, which is a lot of miles driven yearly for such an old car (THANK YOU Pontiac).
The engine has a HV3, and the car is in above average condition overall, and I plan to keep it running as long as it will go.
The transmission has a slow shift between 1-2. It used to slam into the gears way back when it had 80,000 miles, but I had someone make changes to the PCM, so it does not do that anymore. There is no shift kit in the trans, but I have one and want to install it. The transmission pan has never been dropped, so I do not know if there are metal shavings or pieces in the pan.
So, I want to drain the trans fluid and put in new Dexron 3 fluid. But someone recently pointed out that on high mileage transmissions, one should not replace the fluid as that can cause the transmission to start slipping.
So, should I change the trans fluid or not? And should I install the shift kit?
