You should be able to block the truck up at the steer axle and gain access to the crank pully from the underside, If your going to this much trouble, you'd be better off in the long run to replace all of them at the same time, 'cause sure as the sun will come up tomarrow, the altenator belt will break next week. Just remove the 4 bolts and slide the coupler shaft twords the Hyd. pump, you'll have to remove the alt. belt to install the new belt anyway.