i would check what they call the throttle valve cable it runs from your vp 44 to the trans on the drivers side of truck there should be 1/32 in slack or play in cable works best to adjust it with two people adjustment is at the vp44 pump just need to remove the small plastic cover over pump

 

Good info

 

mine did that too would not make shift from 1st gear but my engine also derated or went in to limp mode it was the output speed sensor . check the codes . the truck was acting funny about 2 week before it totally failed.

 

I had the bands adjusted and it helped

 

Changing the governer solenoid and pressure transducer is very easy, right under the pan, takes about 15 minutes, I think I spent about 100 bucks on the parts, if that what the problem is I dont know.

When mine went stupid it would just hang in first gear or never go into first and start out in second.