The rearward facing PTO on the transfer case is for trucks like the M49C, M50, and the pipeline construction truck that have a pump or winch mounted behind the cab. A front winch uses a PTO attached (in a deuce) to the left side of the transmission. Both use a shaft or shafts to operate the accessory and sometimes, in the case of a rear winch, a chain and sprocket too. M817 dump trucks use a double ended PTO to run both the winch and the dump body . A M816 has 2 ptos and the one to the rear is further split by a power divider to operate either the crane or the rear winch.