4l60E slipping on 2nd and 3rd
 

Hi
I have 4x4 95 V6. I can drive it normally but when Im on 2 or 3rd gear it just slips , I can accelerate and overtake but if I push to hard it can go redline still accelerating. I need to be very carefull not to push it to hard on those gears
It drives fine on 4th -> lockup engages and I see no slipping there but it feels like it has no power, it likes to downshift (maybe it should work this way, my first car is srt so I cant compare). 1st and reverse works fine, will do burnouts.
Noticed that on park and idling after a while temp of the engine gows up..
I have changed solenoids A and B, no results. Changed the fuild and filter,no result. Only saw a bit of a sand in the pan.
Any advice?

Rebuild, plates are shot

ohh simple as that :) ok but could be there any malfunction in valve body to look for which caused plates to burn this way? Or cooling system which I have noticed isnt operating correctly could cause to fail the clutches?

or it was abused by prewious owner