Vancouver 4 Wheelers

 A buddy of mine that would love to be part of Vancouver 4 Wheelers some day is working on his old Jeep. It is a '77 CJ5. The drive lines are spinning but it's not going anywhere. It has a Dana 44 in the front and an AMC Model 20 in the rear. (from what I can tell) AMC Model 20 is the only round 12 bolt I could find on the net and it says it was available on Jeeps from 1976-1986. Anyone know anything about the AMC Model 20? Where to get parts, reliability etc? We are going to crack it open soon to see if we can tell why it's not moving. I am not sure what to look for so I hope its something obvios.

20 is normally a pretty reliable axle. Not real sure but I don't think it's a c clip axle and has a pressed on wheel bearing and a retaining plate. Could have a broken axle and the broken piece is just spinning. If it's an open diff only the axle that didn't have a load on it would turn. Jack up one side and then the other and try to spin the wheel by hand and see what happens before you break open the pumpkin.

Also, some of the AMC 20's used a two piece axle shaft. If that's the case check for bad splines where the hub meets the axle. Would cause the same effect as a broken axle.

 Thanks for the input. It looks like he has a broken axle. He ordered a new set of Moser one piece axles. From what I read if you upgrade to the one piece the AMC 20 is almost comparable to the Dana 44. I hope so because he plans on pounding on it.