Dresser TD8E, been sitting about 6-7 months, cranks up and motor sounds great but will not move at all. When not running, can move driveshaft a little, about the same as a rear wheel drive car in park on a lift. When running it has no free play, as rpm’s go up you see the shaft slowly torquing up and moving couple degrees but once shut off it goes back to same position as before. Had no previously known issues. Friend said it ran and operated fine. Cult CNN pressure is on higher end of green. Has a winch on it. Is it possible range valves are stuck and two gears enabled at same time? Shifting in any gear or direction changes nothing.
Does it have a winch by chance? The driveshaft while not running should be able to be turned pretty easily due to no hydraulic pressure to apply any clutches.
Dry or wet back end ? Brake bands may have rusted to the drums if its dry . Still could be the brakes wet or dry .
What drives the winch rear of the input shaft?