[Carl n Susan]

While there are shear bolts in hydraulic systems, it is extremely unlikely two (or more - the OP has never stated what type of Montana they have) failed at the same time. Even if a shear fails I seem to recall the slide gets crooked.

If the motor runs as described by the OP and it reverses direction depending on which side of the switch is depressed, one has to believe the problem lies in the pump or further outboard. The 1/4" drive at the end of the pump forces the pump to spin. I don't know if counter-clockwise is the proper direction for retraction, but should have caused the slides to retract or extend slightly (with a noticeable load on the pump motor). Lacking the OP noticing any of these signs re-enforces the problem is in the pump or further out.

Since the OP hasn't observed hydraulic fluid leaking anywhere, or that the level in the reservoir is dropping the longer the motor runs, one has to assume the hydraulic lines are intact. As there are two or more cylinders, one or more would still extend/retract even if one had failed internally. So that only leaves the impeller in the pump. I conclude it has failed and is not providing any pressure. Of course I would have it tested before plunking down $$ for a new one.

The only concern I have is this type of failure is very rare. I don't recall hearing anyone with a failed impeller before. Motors fail, lines break, and seals leak, but impellers - not so much.

Getting the slides in without a pump is a challenge. Overcoming the internal hydraulic pressure in the slide cylinders is the problem. Perhaps disconnecting the hydraulic lines would work? I don't really know. Even if the pressure can be overcome and slides retracted, how do you keep them that way as you drive to the repair shop?

Sounds like time to call a mobile repair company and let them take a look at the problem.