rear diff fluid frothy?

hey guys another question bout my 97 z71, after running the truck thru the gears while rear was on jackstands before i removed the rear driveshaft (for noise identification) i decided just to go ahead and remove the rear diff cover, i just bought the truck and was going to change all the fluids anyway, when i pulled the pan all the way off the oil looked so frothy, like i ran it through a blender, what causes this? there were no leaks on the diff or the seals.

hey guys another question bout my 97 z71, after running the truck thru the gears while rear was on jackstands before i removed the rear driveshaft (for noise identification) i decided just to go ahead and remove the rear diff cover, i just bought the truck and was going to change all the fluids anyway, when i pulled the pan all the way off the oil looked so frothy, like i ran it through a blender, what causes this? there were no leaks on the diff or the seals.


the rear diff fluid should be dark and of a thick viscosity..If its whitish looking and thin this may mean the vehicle was run in very deep water, also the diff venting must be intact , and routed correctly..on a 1997 not sure how this was routed ..

I would put regular engine oil in it to flush it then using rags with paint thinner [mineral spirits] wipe in down best you can and use a air compressor to blow it out ..

the wheel bearings may after some time , give you trouble , if the water got to them ..

well, turns out both pinion bearings were chewed, i just had my rear end rebuilt and the noise is gone :) now for the brake issues, if anyone has ideas please see my other post bout the brakes, thanks guys.