Transmission slip 1979

[levittown]

My 1979 corvette with automatic transmission slips out of drive after about
45 minutes of driving. I can down shift then it will go back into drive for
a little while, then slips back out ? I'm a back yard mechanic ,but in the back half of the back yard!

 

[black_81_vette]

Its going to need a rebuild....The fluid gets hot thins out and the worn clutch apply seals cant hold pressure causing slippage.

 

[TimAT]

First, pull the dipstick and smell it. See what color the fluid is. If the fluid is dark or has a nasty smell, figure on a rebuild. IF it's nice and red and not stinky, Drop the pan and see how much trash is in there. It could be anything from plain old worn out seals to a partially plugged filter. On the good side, a backyard mechanic- even one that's way out in the backyard, can rebuild a TH400 with a little time and effort.