My 02 cummins with the 5speed has a brand new 13in clutch in it and brand new hydraulics and the truck does not want to go into gear when it is running. When i shut the truck off it goes into every gear easy. What could this be and how do i fix it ?

 

a couple weeks ago i replaced the input shaft in my buddies truck n we got er all back together n had the same problem. tore it all back apart n figured out i put the clutch disc in backwards...

 

well the truck ran for 90 miles just fine and then it just quit