Hey scotty, so my 07 grand prix is still running strong but I'm still having a small problem with rough shifting with certain acceleration. Was wondering if its safe to use a Transgo 4T65E shift kit at high mileage..? (160,000)
If you're going to start tinkering with the tranny then you might as well rebuild it. A shift kit won't fix a worn out transmission.
You can go that route.
My Buick 2005 has the same transmission. I have not used the KIT yet. However it depends on the issue. My car was acting up and shifting hard from 1st to 2nd and 2nd to 3rd when it warmed up. Once the car was shut off for 15min it worked fine till it started doing the hard shifts again. I have serviced the transmission every 30,000 miles with drain and fill and filter change since I have had the car. I also installed a transmission cooler since I saw that hard shifts happened at a certain temperature. After along time of trying different things it turned out my MAV sensor was going bad. I replaced it with a new after market one twice (cheap non OEM stuff) since the issue came back after driving 3-4 thousand miles. Then I went all out and got OEM MAV sensor. Since then the car has been working fine.
If your car is doing the same thing you can try the KIT. The shift kit will be a bandage and if you have never serviced the transmission or drive the car hard the transmission may be too far gone. It will cost you $500 or so to get it installed or $200 if you do it yourself. No harm in trying on an old car with the current market we have.
