Transmission problem

Good afternoon.

Check you fluid level first.

Make sure the differential is not the problem. Check and see if the drive shaft is turning but not moving the truck. See if the speedometer is working.

Beyond that, drop the pan and inspect for any debris in the pan. See if the filter is heavy or clogged. A clogged filter will rob fluid to the front pump for proper operation.

Beyond that, it is an internal failure.

Roy

https://www.2carpros.com/articles/automatic-transmission-problems

https://www.2carpros.com/articles/how-to-service-an-automatic-transmission