Join Date: Jun 2009
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Strange noise in Differential
I would like some help diaognosing a strange noise I am hearing occasionally from I beleive the rear Diff.Of a 1991 Chev Suburban 2500 Diesel.
The noise sounds like a fast Sewing Machine,or like you are dragging a "ratchet strap",this is accompanied by on or two "thump's" (like the rear differential is locking) then its all back to normal.
I changed the rear diff fluid and filled it incorrectly with a normal 80 W90,I changed to 80W 90,half a gallon about, that was for limited slip diffs but the noise still occurs sporadically.Whilst this noise is happening I have shifted the transmission into neautral and the sound still occurs with the same pitch.
Recently I changed the wheel bearings,perhaps I upset the "Sipders" in the diff?I took the rear diff cover off and jacked up the Axels,ran the Truck with its wheels off the ground.As luck would have it ,the noise didn't happen for the experiment.
However with my foot I was able to slow one turning wheel,untill the diff would lock,however the wheel would spin free again.Ie the diff lock would disengage.
I have videoed the above and am waiting for it to upload.
Any help is much appreciated.