Q: Truck won't move while in gear

Hello and thank you for your question. The problem could be 3 different things wrong with your truck. First, look at the brake system to ensure that the brakes are not engaging when you put the vehicle in gear. If the brakes are okay, then the problem lies within the transmission or transfer case.

The transfer case could have the shifter placed into neutral causing the vehicle to not move. Try tapping on the shifter motor on the transfer case to see if it is stuck. Then start the engine. While the transmission in park, put the transfer case in 4wd and then in 2wd. This will make the shifter motor move and engage the transfer case into gear. Then put the transmission into gear. If the vehicle moves fine, then you would need to replace the shifter motor on the transfer case. If the vehicle does not move, then either the shifter motor is not functioning or the transmission is failing.

You could have a problem with the input shaft seals on the transmission. If the drive circuit and reverse circuit seals are split on the input shaft, then the transmission will statically lock itself. The fix to this is to take the transmission out and replace the input shaft seals on the input shaft. To have this diagnosed, I would recommend having a certified technician like one from YourMechanic, diagnose the potential transmission issue and advise you on the proper repair.