4l60e operates like clock work until the tranny gets hot. Once at or above normal temps it slips. Won't change gears. I have to put it into first and even then it revs to about 4k before it moves. Can anyone help diagnose the problem?

 

you have one or 2 issues either a marginal pump or a leak in the forward circuit most likley in the forward piston. depending on what yr trans you have it could be a broken forward piston or just hardened bad seals..when the fluid is cold its thicker and can seal howeverwhen it gets hotter its thinner and can bypass the seal. what yr is your car

 

Its a '97, but the transmission was replaced about a year and a half ago. Only has about 1000 miles on it

 

Scan your computer for trans codes. I think your transmission is being forced into a limp mode condition once it gets hot.

 

Will a regular ObdII scanner work?

 

Yes that should work to retrieve the codes.