4L60E issues...

[davbrucas]

The tranny in my truck intermittently slams the 1-2 and the 2-3 is firmer than usual. Other times it shifts perfect. There's a CEL that it throws every once in a while but the light goes out on its own after a few key cycles. I've pulled the code but cannot remember what it was.
Any ideas?

Truck is a 2010 Silverado 5.3L.

Thanks.

[twicepipes]

Your truck has the 6 speed auto IIRC, and not a 4L60e.

My 99 Silverado had a similar problem and a new valve body fixed it. Totally different transmission though.

[VaderTT]

6lx0e