how to check gear oil

Hi rayan, Your rear differential has should have a drain plug (located somewhere near the bottom) that can be removed to drain the gear oil. If not, the cover will have to be removed (which is very messy) in order to be drained. Reinstall the cover or drain plug before refilling the differential. The filler plug should be on the top half of the differential. Pump fresh gear oil into the differential to the recommended level and then reinstall the filler plug. Hope this helps!