Duratorque axles became standard equipment on all
1961 Airstreams. I have heard that at least some were welded in place for California built trailers into early
1962. Not certain if Ohio also welded them in place in
1961 and possibly very early
1962, but the axle on our
1962 Safari was bolted in and it was in the first 25% of the Safaris built in Ohio that model year.
As previously noted a 1962 Airstream will not have a gray tank. The black tank will be above the floor directly below the toilet and will only hold perhaps 10 gallons at most.