Hello, I have a 1995 sls with the 4t80e transmission. My car had the not shifting issue ,everything else worked fine. I bought the 1-2,3-4 shift solinoid kit as described and my mechanic did the install. He normally is very good, he verified the procedures and confirmed the placement of the little ***** in the lower valve body area, confirmed solinoids were recieving and activating with signal and confirmed linkage all worked properly before closing up and filling with fluid. Now the car won't move at all, it does'nt even change engine rpm when shift though the gears. He pulled it back down and rechecked his work and it still won't move. I drove it up to his shop I guess in limp mode, total distance in that mode may have been 5-6 miles. The shift solinoids were backing out and one was cracked. Any suggestions will be appreciated. I have replaced many items on this car trying to keep it a good one, but now I'm beginning to run out of ideas and patients. Help !!

 

My only thought is that he may not have gotten the little wire linkage from the valve body to the shift linkage connected properly. Depending on the year, there is a small plastic clip that can, and normally DOES break when removing the linkage for the manual valve in the valve body. If the manual valve is not connected, it can create a no move situation.
You may suggest dis-connecting the tans connector, and seeing if the car moves. Disconnecting the connector puts the trans in another gear...if the car then moves, there is a problem with how the valve body was re-assembled. If it still will not move, I have to say the manual valve linkage is not connected.

 

Thanks for responding Adam, my mechanic stated he thought all that was okay, haven't tried the test yet. If the plastic connector is broken can it be purchased at a Cadillac dealer, and whre is it located, on the outside of the tranny or the inside. I would like to contact you as I am in Arlington and could use someone with better knowledge than the guy that is working on my car. He is good, but this has now gotten out of his range.

 

The plastic clip I mentioned is inside the trans, but can be gotten to by removing the lower pan. I believe they are still available from GM, but I really do not know. My parts supplier(Transtar) stocks them, and I have a few in my toolbox.
all you/he needs to do is remove the bottom pan again, and look up in there...if the linkage is just hanging, it will be quite obvious. This is all assuming it has the plastic clip to start with. Some of the earlier trannys had a metal clip. It would sometimes also work it's way off, but not as often as the plastic clip breaking. If you click on the pic in my post above, you'll see the clip, and the location, although the pic is showing the metal style clip.
btw...I live in Duncanville, but I work in Plano....