Rear Differential question

[mikey4563]

Hey guys,
So I just recently had my rear diff rebuilt because I was getting the pinion hum at around 45 MPH and my pinion seals were pouring fluid. Had the rebuild done and all is quiet and no leaks but now whenever I hit 60 MPH I hear the hum again. it used to start up around 45 mph now when its 60 I hear it again but its very faint. As soon as I go over or under 60 it goes away though. Any ideas? im kind of at a loss.

 

[99french]

If you reused the gears that can be the issue. When gears are installed they get a certain wear pattern and when you reuse them in the case of a diff rebuild they then take on a second pattern resulting in some noise. You can try a thicker fluid.

 

[mikey4563]

hmm okay Ill ask if the shop reused the gears and if not ill try a different fluid. Thank you!

 

[RicketyExplorer]

Usually a rebuild is just new bearings and seals, I agree with 99 try a thicker fluid or a pure synthetic or add some lucas in it.

 

[boominXplorer]

Put some miles on it, the hum should go mostly away after 500 mi or so after the new bearings. If it gets louder at all you have an issue.

 

[mikey4563]

yeah ill mess with the fluid and put some miles on it. if anything I have a one year warranty on the parts and labor of the rebuild so im good on that