rear diff fluid frothy?

[mybad_z71]

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.

[j cAT]

Originally Posted by mybad_z71

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 ..

[mybad_z71]

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.