I talked with someone back in upstate NY who bought a '96 impreza recently. He took it on a rocky dirt road, and where it was steep, he was spinning 1 wheel and could not get traction. He says it "cluncked", and the the AWD worked, then it would spin a wheel again. Once in a while it "clunks" and the AWD starts working briefly. It's an auto I believe. I told him it sounds like the center diff is toast, but what do I know. Anyone have a more educated diagnosis, or what it will take to get it fixed? Junkyard trans? Repairable?
The auto does not use a center diff, they use a transfer clutch pack that is applied using a pwm solenoid (and fluid pressure) that is controlled by the tcm based of of various inputs. You may give me a call @770-789-4928 and I can give you some options, STAY AWAY FROM JUNKYARD TRANSMISSIONS on this particular unit.
Sounds like an axle shaft may have popped out. Tell him to check the rear diff axles to see if one's out further than another. The behavior you describe could be a few things, but that's the easiest to find and fix.