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Originally Posted by c.zellermaye
It's 26'. So do you think I have an issue here? I'm so new to all of this that I don't really know what I could be getting myself into. Or how to evaluate the potential of a problem.
Of the two possible problems, frame sag is unlikely in a 1966
Overlander -- not impossible but unlikely. Frame sag can be identified by a bulge in the side skin behind the wheel wells or sometimes over the wheel wells. In serious cases, you can even see a crack in the frame in the vicinity of the axle mounting plate. There is a factory repair kit for this problem, and it is a somewhat expensive repair.
Rear end separation, however, is quite possible. With rear end separation, the body structure has become separated from the frame allowing the body and frame to move independently of one another. This condition can be idnetified by bumper movement away from the body under pressure -- example have a partner sit or stand on the rear bumper and observe for an opening that may develop between the frame extension to which the bumper is attached and the body. If a gap develops, there is at least some rear end separation present -- and in most cases some rot in the rear floor area -- usually near the perimeter of the one-stop-service-compartment (rear trunk).
I had rear end separation repaired in my Overlander nearly a decade ago, and even then it was nearly $2,000 for the repair itself and the patching of the floor in a small spot where rot was discovered.
Good luck with your investigation!