Trans Slipping

[fishlips]

I am having a problem with a 2006 5.3 and a 4l60E. Bought the engine and trans together and both are stock with stock ECM and harness (modified to work in my 66 El Camino). When cruising everything is fine. Even under moderate acceleration it is OK. When I stand on it it will slip some as the RPM climbs but not too bad. Then at about 4500 RPM it just lets go and the engine will buzz. The initial slip feels like tire spin (open rear end, no posi) but when it lets go it is like you put it into neutral. I lift off the gas and it will up shift and does the moderate slipping in the next gear. Any Ideas?

[TonyB4]

I would get it to the dealer and have them take alook at it. Sounds like you could have broken the retaining ring that holds the clutches in the canister.

Did you have any codes pop up?

[Reucroft]

Oh dear. Sounds like your bands are not gripping. I had exactly the same thing when I supercharged the C5 vette. The 4L60E tranny only lasted 200 miles. Raptor rebuild kit from www.transmissioncenter.net

Check your tranny temperatures if you can. Anything above 200F start to worry. Do you have TCC lock up? This will help get the temperatures down if you cruise in Apply, after you've been putting the power down.