there is a vent on the rear end right where you are talking about check and see if the hose s cracked.. i would pull the filller plug( drivers side even with the driveshaft. i think yo just use a 3/8 extension on your rachet.) on the diff and check for fluid. you should be able to stick your finger in the hole and feel fluid. you can fill it up till it comes out you use 80w90 oil. you need special additive or oil if yo have liimted slip which i dont think you do. your seals would leak around the wheels. a whine/ click could be a ujoint. check the fluid level and get back to us. on the drivers side door jamb is your certification label. the axle code is on there. if it is an 86 it is the same as mine.
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