the only difference in axles 79-85 to the 86-95 are the axles on the later trucks are 1.5" wider on each side so the shafts will not interchange but the 3rd members are the same 79-95 and the 79-85 front 3rds are the same too. these are all 8" ring gears. there are different backing plates and drum setups too but thats not going to cause any major issues.