I installed a potentiometer in place of the tps. Now the transmission either does not shift into OD at all or it shifts immediately after shifting to 3rd depending where the potentiometer is set. It also stays in OD untill I come to complete stop. There is one spot on the potentiometer where Any more adjustment to the left and no OD any adjustment to the right and it goes straight to OD. Almost like a switch

 

Is this something new to performance enhancing? I'm not sure why you would replace the TPS (which is a potentiometer) with another? New transmission in a older non computer truck? It is a balancing circuit, so as resistance goes up on one wire to the common, the resistance goes down on the other to the common. If this is an aftermarket thing, do you have the correct wire on the common, and the other two on the correct outputs?