Raising the cab should be in the operators manual. If not, find the cylinder and trace it back, don't forget the lock.
Beds usually stick up because the pins are binding at the pivot, the cylinder is binding, or the valve is not releasing the pressure completely.
If it gets better when warm, then the fluid is just too thick. In that case, you could raise it with a load but not dump a few times, let it down and raise again to warm the fluid.