Engine slips-mechanic confused

Anything higher than 2nd taking off while bobtail is too high. I don't care what anyone says. Taking off in high gears is abusing the truck.

 

Just a fwiw, nothing more..(not by any means a mechanic)

My last truck did something similar as what you are explaining. I was told that it had to be a faulty slave cylinder on the transmission..Unfortunately mine was an 18 speed, not a 10.
It did it mainly when it was cold, or climbing under load. Luckily I got 2 years, 200k miles running it this way before I traded it in.

 

Omg!

Tell your boss to get the clutch adjusted before you end up stuck in the middle of the road unable to move and holding up traffic.

if the clutch can’t be adjusted, it needs to be replaced.

there is only one way the engine can rev up in gear and not move, the clutch is bad or out of adjustment.

seriously if he has to save for a clutch and you hope it can be done before winter, your boss is very cheap and you shouldn’t be working for him.