99 silverado 4x4 noise

[luvallmotorsports]

I am working on a 99 silverado 4x4 for a customer. He's trying to sell it and it has a noise when in 4 wheel drive. It is a whirring or howl that shows up at about 35 mph and up. It is worse when decelerating and it also binds up terribly when making turns. I've checked u-joints on both shafts, found the wrong fluid in the electronic transfer case so changed that and still has the noise. My boss ordered a used case from a very reputible recycler and we installed that case and the same noise and binding are there. Does anyone know if these had problems with the front diff making noise like this? Any advise would be appreciated.

[j cAT]

Originally Posted by luvallmotorsports

I am working on a 99 silverado 4x4 for a customer. He's trying to sell it and it has a noise when in 4 wheel drive. It is a whirring or howl that shows up at about 35 mph and up. It is worse when decelerating and it also binds up terribly when making turns. I've checked u-joints on both shafts, found the wrong fluid in the electronic transfer case so changed that and still has the noise. My boss ordered a used case from a very reputible recycler and we installed that case and the same noise and binding are there. Does anyone know if these had problems with the front diff making noise like this? Any advise would be appreciated.

these are part time 4wd vehicles ...if the front tires are of a different size / different wear and this customer operated in ANY 4WD POSITION ON DRY SOLID PAVEMENT this is usually what occurs ...the binding is the gears being worn and some have had them lock up solid when going at hwy speeds NOT GOOD !

FRONT DIFF TAKES 80-90WT ...TRANSFERCASE TRAC II fluid....if the transfercase fluid was black its n/g...the front diff if damaged will show gray oil and metal particles will be present if n/g....