I have recently purchased a 2000 MC SS that had some transmission issues i.e. slipping out of gear and not going in gear. Everything I have read suggests to do a full fluid exchange with new filter before I do a swap as that fixes most of the issues. My roommate who had driven it from the shop to the house, said it had slipped/gone out 4 times in a 35 minute drive. The car has 307k miles on it and I do plan on changing out parts. Any suggestions would be great.

 

With that kind of mileage, I honestly wouldn't waste the money. If you intend to continue to keep the car, I'd put that fluid and filter money towards either a junkyard trans or a rebuild (preferably the latter if youre trying to keep it significantly longer).

With that kind of mileage, it's already beat probably 90%+ of the other 4t65s out there so I sure wouldn't bet its got any useful life left - especially on the wear components.

 

Full fluid change will probably make the trans inoperable. You need all that burnt/worn clutch material in there or it wont function properly anymore. I wonder if a full fluid change was done right before you got the car. Hows the fluid look or smell?

Best bet is to get a brand new trans.

Funny, I think my bonneville was at 307 for its last trans rebuild. Sadly it went to the junkyard about a week ago

 

I had a feeling as such but I wanted to get opinions from more experienced people first and these responses are all greatly appreciated! Seem my best bet would be either a brand new trans or buy a rebuilt one then swap out.