[BlueJeep]

So now for my question, is anyone an expert on 4L60E's? Mine shifts into all 4 forward gears nice and smooth when it's cold, but when the truck warms up...and only sometimes....I lose 3rd and 4th gear. When I shut it off, let it sit for a few minutes (like running into a store), and start it back up my 3rd and 4th gears are magically back...for a while. I have no error codes logged in the ECM, I have no slipping in the transmission. My fluid is at the proper level and is not burnt. When I lose 3rd and 4th, it's always when I slow down for a stop and go to accelerate again, I never just lose them while driving in those gears. What it does is just stays in second gear and pulls more RPM's, it doesn't ever slip. Manually shifting through the gears does nothing for me at this point.

Any ideas? Any transmission geniuses out there?