I noticed in my owners manual that the front diff takes 80w-90 diff Oil. I am interested in using a Synthetic when I service it. All I can find in synthetic 75w-90 Diff oil. Will it cause any harm to use the 75w-90 synthetic in the front diff?.............

 

No harm in using the 75w90. The number you need to look for is the "90" part, that's the viscosity of the oil after it heats up.

 

Thanks!