I recently did a transgo HD2 shift kit and servo in my 2005 gmc Sierra with a 4L60e. Did everything as instructed and I'm having an issue with shifting. I have no reverse and no first gear. If I leave it in drive it doesn't move until it gets harder throttle. If I manually shift it takes off from second and goes through the rest of the gears and back shifts once it's in drive. Any ideas where to start checking?

 

Sounds like it is something in the valve body.

 

I have seen a thread like this before. Try searching or wait for Vince/Gilbert to answer. Pinched wires maybe. Can't remember.

 

did you make sure you got the check ***** all back in the right spot? Not sure what the outcome would be if they were out of place, but I know they can be finicky

 

Everything was done exactly as instructed. All the check ***** and correct colored springs matched. The buddy that helped me is a master tech not to say we didn't miss something. It's going down to a friends shop in a week he's a GM tech so we will see what happens. The trans only has 60k on it so I hope it's nothing major.

 

I would look at the location of the 3 8mm "B" valve body bolts. If these are not put in the correct location you could lock the sun shell in the case. With this happening you will not have reverse and I'm pretty sure that it would bind in first gear. Let us know what you find. Vince