pwrcat

I have a 2003 Silverado with the Allison Transmission in it. Long story short us that I had to replace the rear end and the adaptor plate on the trany for a four wheel drive and transfer box.

After putting a different rear end center assembly in it I am experiencing the following.

1. It goes from Park to Reverse and Neutral perfectly. No jump or anything, and it drives in reverse perfectly.

2. When I go into Drive it kind of jumps and it feels like it is staying in third. Meaning it takes off in third and will not shift up or down.

I do not think it is anything to do with my trany being installed wrong but more like a sensor or something telling the truck it is in third gear?

I have not removed any battery cables to reset the computer or anything, and I am told there is a sensor on the rear end but I cannot find one at all.

When the truck broke what happened was the rear end seized up and snapped that adaptor plate and all kinds of stuff cam lose and broke under the truck. So I am wondering if it has torn a sensor out of place or if it needs to have the computer reset or what?

Any ideas?