The auto's had the 21 spline DLD (Dodge Light Duty) T-Case, while the manual equipped trucks had the 29 spline DHD (Dodge Heavy Duty). They ARE NOT interchangeable unless you swap inputs. The DHD had a larger drive chain for the front axle, which is desirable, but not a huge deal. I'm gonna bet you grenaded the input planetaries like I did, seems to be a weak spot in them.

 

shifter fork thanks for the ideas guys