Please help with od problem!
 

So there are a few things here and I don't know exactly where to start. I had my tcase replaced recently and after install the tranny fluid never got topped up, and then was drove to test. 😁 it made a terrible screeching sound and then was topped up. (and tcase was drained and refilled.) the 4x4 indicator switch was broken so there is just a plug on the tcase for now. There was no Vss on the tcase replacement so the old one was taken off and put on.
When I drive the truck now it doesn't shift into od. I can get to about 50km/hr then let off until it hits 40km/hr and give it gas and it will shift into od. But only stays if I slowly accelerate, if I stomp on it it jumps out of od. My speedo works still (don't know if speed is accurate, since I have 35's on)