My diff has always had a bit of a whine at highway speed, nothing serious. I've been running synthetic oil in it, and was thinking of switching back to regular oil, possibly something slightly thicker to reduce the noise; especially since I am about to install poly subframe bushings that can transfer more noise and vibration to the chassis.
Any suggestions? Is there a brand of gear oil that makes a mildly thicker blend?
Any suggestions? Is there a brand of gear oil that makes a mildly thicker blend?