So I get in my D the other morning and drive off to work and everything was fine. When i got to leave the parking lot at lunch I put it in reverse and gave it some gas and the transmission is slipping so bad in reverse, but it still able to back out. Also there was some vibration when i backed out that i normally never felt. I drive around and all my forward gears are fine. No slipping, vibration, or hesitation. So my question is what would it be?

 

I would check the trans fluid first. Look at it and smell it. If it is black and smells burned it needs to be changed badly. In my experience if it is really low this can happen to.

 

Could have broken the band or finished off the lineings. You could try to tighten up the reverse band slightly on your 46RE transmission. Don't forget to replace the filter while your in there and hope. Also look at your magnet and clean it off and look for anything that could have broke.

(1) Raise vehicle.
(2) Remove transmission oil pan and drain fluid.
(3) Loosen band adjusting screw locknut 5-6 turns.
Be sure adjusting screw turns freely in lever.
(4) Tighten adjusting screw to 8 N·m (72 in. lbs.)
torque (Fig. 73).
(5) Back off adjusting screw 2 turns.
(6) Hold adjusting screw in place and tighten locknut
to 34 N·m (25 ft. lbs.) torque.

Mopar