OK, I just bought a '94 (I know it's a 4thgen) Z28 for $2400 because the tranny slips. Bad. The more I drive it the more I think the converter is bad...it slips badly in all gears until the converter locks up. Slips worst in first and second. It just had a shift kit put in about 4k miles ago, and it has 103k on it now. The slipping started all of a sudden so I'm starting to think the converter clutch is shot. Reason I'm asking is because I have a spare 4L60 converter in the garage and wonder if it's worth it to put it in and see if it helps. I plan on having the tranny completely redone in the future with a Vigilante converter and everything.

Also, after the shift kit was installed, I lost the over-run clutches in all gears. What should I look for to fix that?

Thanks for all your help, I'm just not a tranny man.