This is a common problem on the 4L60/65E. The TCC regulator apply valve wears and then won't fully apply the TCC, often it is worse as the unit warms up.
Check the TCC solenoid for hair line cracks on the "neck" of the solenoid. It is also possible there may be a hidden crack inside the solenoid that is not visible without disassembling the solenoid, the seat area cracks.
Sounds like a bad tcc solenoid.
Monday, May 17th, 2010 AT 7:58 PM