I want to replace the rear differential's axle seal

Remove brake calipers to reduce load on axles, use an in/Lb tension wrench to determin the turning load of the pinion, as you need to re set this as close a possible to what is set now, this diff uses a collapsible spacer so over tightening will upset the preload, if over tightened you can't just back it off, a new spacer and full preload set up will have to be done, also mark the alignment of the flange on the pinion shaft for correct re alignment on installation, see pic for exploded view of pinion seal set up.

I replaced the differential's oil Seal which is which is located next to the flange. Since we initially failed to count the number of turns and mark the location of the flange in relation to the rest of the differential before removing the old oil seal when tightening the nut back we simply tightened it by very small turn amounts, one at the time until we noticed no more up and down movements of the pinion shaft. Now when we tested the vehicle we noticed a small humming noise between 50 and 60 km/h only. We would appreciate your help in telling what to do to get rid of this noise. Thank you for your help.

Jim

You will have to do a new preload set up, you will need a new collapsible spacer and check that the pinion bearings are ok, no pitting and no wear marks.