I think there might be something wrong with my 4L60E?! It is a stock tranny with vette 1-2 and billet 4th servos and of course a tune....it is behind a cam/heads/intake Lq4 with bolt ons. When I first start it and take off on cold mornings, it shifts fine part throttle, but if I go WOT from a dig or kick it down to pass, it seems to be slipping in first gear. It pulls normally til about 4500rpm then the rpms drop about 500rpm, raise back to 4800 or so and pulls normally til about 5800 them it kinda lags the 1-2 shift. Then it pulls normally through 2nd and 3rd. After driving around for 20-30min and warming up, it does fine. Ive checked the fluid and it appears to be fine. The fluid is a good transparent red color with no weird smells. And with the engine running in park, my fluid is halfways between the C and H marks on the dipstick after idling for 5-10 min. The truck put down 391rwhp in 3rd with the convertor locked 2 weekends ago on a DynoJet dyno. Could I have something going bad in my tranny? It only has about 50,000 miles on it.

 

Also, my 1-2 shift rpm is 6,000, and it kina hangs about 6,000 rpms before it shifts into 2nd.

 

Where do you have the tcc set to apply and also how cold is it in your area these days? Its kind of weird that the rpms are dropping and almost sounds like your tcc is not applying when your truck is cold. Seems to be a common complaint this time of the year. Is is possible that the rpms drop because you lifted on the accelerator peddle?

 

I definitely didnt lift the skinny pedal ....I've been able to duplicate issue every time. And the TCC apply/realease points are stock for an 05 SSS tune. I don't have an aftermarket convertor. The coldest temps here so far have been in the high 30's to low 40's with wind chill. The truck is stored in a brick shop with the heat off at night.