Check air compressor for ARB's and engage the air lockers, if oil comes out the solenoids, seals are bad, deduct fro price to get them fixed. Compressor, if ARB of that vintage, will most likely be noisy and take a few minutes to come up to pressure and will probable cycle every 25 - 30 minutes. They seem to last forever even though they sound like there going to throw a rod...
Dana 35, locker, 33"s or larger - asking for boom. Had one, fully polished turd too, Warn full floater, hardened axles, ARB locker, thought it would be fine under my easy driving style and 4 chipmunks under the hood .... broke it going down hill no less... some people drive on them forever without issue, the next guy breaks his leaving the driveway... In my case it broke 1,600 miles from home at the beginning of a week trip, luckily I had my Grand in the area and salvaged the rest of the trip.