I would make sure that the u-bolts and springs are all seated correctly, and not loose. If something is able to move around back there, it will vibraite a lot.
A quick and cheap way to tell (assuming everything is bolted correctly) if the mild lift its self is the cause (could be on such a short CJ-5), is to throw a couple of hundred pounds in the back, effectively compressing the springs, lets say 2". If there is then no vibraition, the angle is too great, at least for the u-joints you have in.
'82 Scrambler - NV4500/4.5" lift/33" Toyo MTs/4.0/twin stick, and my windshield washers work! Full 1/2 cab Cage
2004 Grand Limited 4.7 HO - OH Boy!
2010 Grand Laredo 5.7 Hemi - SICK - work vehicle -gone - replaced by an 08 Tahoe - nice ride.
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