I have a 4l60E I did my first rebuild on. I used a hd master kit and I have an issues with it coming out of 4 and going to 3rd. If I am on the freeway and it shifts to 4th when the truck comes to a constant speed it will down shift to 3rd. If I give it a tiny bit of throttle it will go back to 4th. as soon as the speed is constant it will go back t 3rd. any help would be great.

Dirk

 

My 02 S10 does same thing. Did you ever find the cause?