1985 Ranger 4X4 with A4LD transmission , 2.8 V6 engine & manual lever in floor for 4X4 & Hi & Low range . Transmission seems to shift & hold properly in forward gears . With transfer case in Hi range & the truck on the level or a very slight incline reverse works as long as you are easy on the gas . If on a steeper incline or if you goose the engine reverse lets go & just slips .
With the transfer case in Low range the truck will back up steep inclines & will spin the tires without slipping . I would think if it has a pressure problem or worn clutches or bands causing the problem that it would also slip in Low range before spinning the tires . Fluid has been changed & is at proper level on the dipstick . What do you think ? TIA
Also torqued the bands & valve body to specs.

 

sounds like you either have a stuck valve in the main control or you have a reverse band that is bad. i would first remove the main conrtol, inspect the separator plate gasket for tears or spots where it is blown, remove the reverse piston and inspect it and the bore for wear, and then remove the reverse valve for sticking or wear before disassembling the transmission