Rear End Howl

[joachimf]

@grn03exp,

we had a similar problem with our ’02 at 80k mls. When going through Ford TSBs sooner or later you ‘re going to stumble over the diff issue. But before digging into this I’d try to find out what it really is. A running out wheel bearing has similar sound signature. Read my experience:

http://www.explorerforum.com/forums/showthread.php?t=334104

 

[JesseLamba]

I know this tread is really really old now, but I had a similar issue in my 05 Explorer, and turns out all it needed were new front and rear diff seals. My truck was making that noise for the longest time, and given its mileage and the price I paid for it, I didn't want to spend major money on replacing or rebuilding the diff. But after noticing leaking diff fluid from the rear diff pinion seal, I felt that a bad seal could cause the shaft to vibrate creating the howl. Replace the both the front and rear seals, and the noise is gone.

Just sharing this in case someone else googles for the causes for the diff howl, so make sure you check or replace those seals before doing more major work on the diff.