Intermittent hum when turning right at high rate of speed

elamigowapo · April 17, 2016

So bought this 2008 Silverado z71 4x4 crew cab, after a few days I noticed that when driving over 70 mph and slightly turning right the truck produces an intermittent hum/buzz: doosh doosh doosh doosh. It comes in a steady pattern and increases intervals in sync with speed. Discarding the possibility that it might be a loose panel or shield. So back to the truck, replaced both axles, both front wheel bearings, front left upper/lower ball joints, and got both front rotors turned and replaced brakes. Of course this noise persisted. Again back to the truck, it has a very obvious bad rear differential, it buzzes.... a lot. I tried rotating the tires and the sound persists only when turning right. I have heard cases of people rotating their tires and still having the same symptoms but the tires being the problem anyway. So right now I am left with thinking the problem might be my tires or the differential or something along the drive train. Can you guys PLEASE shed some light. Thanks.

bubbanbrenda · April 17, 2016

My '08 Sierra (68,000) was doing the same thing, except it got to the point it was howling all the time just got worse when I turned either way. I checked everything you replaced, couldn't find anything except the inside edge of all the tires (factory Goodyear Wrangler's) were feathered and slightly cupped, long story short a pair of loaded struts, 2 rear shocks and 4 tires and alignment later it is dead silent at any speed.

NrthrnRdNck · April 17, 2016

Pinion bearing?

elamigowapo · April 18, 2016

My '08 Sierra (68,000) was doing the same thing, except it got to the point it was howling all the time just got worse when I turned either way. I checked everything you replaced, couldn't find anything except the inside edge of all the tires (factory Goodyear Wrangler's) were feathered and slightly cupped, long story short a pair of loaded struts, 2 rear shocks and 4 tires and alignment later it is dead silent at any speed.

Im planning on getting new tires, which ones did you get?? My struts/shocks seem okay though but I can not discard them Im having a mechanic come take a look tommorow. I'll point them out.

Pinion bearing?

Im thinking so as well.

bubbanbrenda · April 18, 2016

I put Michelins on it, and I've had several people tell me there was nothing wrong with the struts but I could tell a difference when I took it off the lift, it was about 1.5" higher in the front(again "loaded" struts) the fact is that my '08 struts were at least 8 years old and have been holding up the front end at least 8 years. The new springs on the struts are starting to settle a little but still about 1" taller than before.