4l60 Trans Problem
 

Why won't this stupid trans shift into 3rd gear when its cold(below 30 degrees) Shifts fine when warmed up.Fluid is good,Filter is good. ???

clutch pack? any sensors? any codes?

Honestly IMO i have the same trans and they are a POS!!! Mine hit the bottom of the barrel about 37k ago and had it rebuilt with a shift kit installed and its even worse when it gets cold out now untill i get about 5 mile of warm up on it...

You need a live data scanner hooked up while its driving to see what the electricals are doing during this time.

Ive got the same tranny, had it built with stage II shift kit, bigger sunshell, 13 vane pump, bigger bands, and I have romped on it scratching tires when it shifts, no problems here in my cammed 2001. The guy who rebuilt it knows what he is doing.