Like the title says, put a new IP in and the truck runs better than ever. Was going to take it on a road trip to test everything out, and no OD.. Short trip. I replaced the TPS last year when the tranny started going in and out of OD, that fixed that problem. Now it's not even trying to engage, no matter how much you baby or hammer on the throttle.. It goes through the rest of the gears just fine. Before I changed the IP, it shifted great. Any idea where to start?

 

First make sure the TPS isn't disconnected.
Then go here http://dodgeram.org/tech/transmissio...TPS_adjust.htm

You can also install a lockup switch either permanently or temp to see if the problem is electrical.
Instructions> http://www.tstproducts.com/Torque%20...p%20Switch.pdf

 

Check the throttle cable adjustment, too.
http://www.dodgeram.org/tech/transmi..._lever_adj.htm