How much you do is really up to you. I usually remove the rear cover, drain and replace the hytran, cleaning any sludge from the bottom of the axle case. Remove the C clips on the axle shafts, pull the axles out and replace the seals in the ends of the axle carriers/housings. Others will pull the axle carriers/housings, and drill drain holes to let fluid drain back into the main case, but I don't do that. Put it all back together, wire brush/sand, prime, repaint. On a rusty rear end, you can use a rust converter prior to priming. That's about it.
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