The proper way:
--Jack up vehicle
--Support with jack stands
--Remove fill plug for rear axle. This is critical. If the fill plug is stripped out (3/8) square drive then you may not be able to fill the axle.
--Remove differential cover, and catch the oil with an oil pan. It will stink a little bit.
--Remove the little bolt that holds the crosspin in place
--Remove the crosspin. It should come out with out to much encouragement.
--Remove wheels and brake drums
--Push the axle shaft in towards the center of the housing
--Remove the C-clip from the end of the axle shaft
--Pull the axle shaft out
--Smack the old studs out with a hammer
--Press the new studs in. A press can be used or a vice and a deep socket will also work.
Avoid using the lugnuts to pull the new studs into place just because it may be easier.
There is risk of stretching/breaking the studs doing it this way. You would not want your wheels to fall off on the highway.
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