Gear Poet

I'm on the road and really don't want to do a tear-down in a motel parking lot. So thought I'd check on this quick here, if possible:

On turning the truck at slow speeds, I'm noticing a rotating sound coming from the rear axle or brake assembly I'm turning into - the noise is on the left side if I turn left, or on the right side if I turn right. It's a hollow, scuffing sound, not a whine, not a grind, not a popping. It is not a u-joint or the carrier bearing - I checked. The sound does not occur while turning at speeds above 20 mph. It does not get worse at higher speeds. Sounds the same turning to the right or the left - but the sound does localize to the right or left side, depending on which way I turn. There is no sound while driving forward or reverse straight, nor any sound on mild turns, nor any sound with the rear jacked up and wheels turned by hand. There are no pops, no loud noises, no vibrations even when the noise occurs on turning. It's definitely locational - on the extreme left when I turn left, on the extreme right when I turn right - does not sound like it's coming from the differential.

It doesn't sound like brake pads shifting into the rotor when the vehicle turns - the sound has a hollow quality. It doesn't sound like axle bearings going out - I've heard plenty of those. Axle outer bearing races spinning made a similar noise in an IH pickup I owned a long time ago, but I don't think that's a good possibility here.

So -

This familiar to anyone? Ideas?

Thanks!

kthiemann

It sounds almost like you may be hearing the clutches in the rear diff. work as you make the turn. Perhaps the thing to do is add some limited slip additive drive it a short distance to let the stuff get in there and do it's job and retest.

tractorguyacb

If its like a wooosshhhhhhhing sound it may have something to do with the brake backing plates. Rust buildup can eventually touch the rotor when it is torqued i.e turns etc.

Good luck

Gear Poet

Winner.

Sprayed graphite on the backing plates. Sound disappeared temporarily. Lot of flex on those backing plates, however - bit of metal fatigue, I think.

Thanks to both posters for your suggestions.