I do not back the rear nut off only the front when adjusting the wheel bearings. I recently did some rear end work on my amphi and found that to pull the axle through you need to use the proper tool and really tighten the nut. Backing it off would only loosen things eventually. I used an air impact to tighten the nut which lined up the hole and allowed the wheel to spin freely.
My amphi now cruises at 65 MPH with no issues though I couldn't keep up with Tommy from Tampa last weekend who was at 70-75 MPH.
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