[Ed Wright]

Might be common, but that does not make it right. I was running one qt in my GM 12 bolt. At Indy last year James Lee was with me. He walked over to visit with Jimmy Bridges. Gear lube came up. James had been galding gears. Jimmy had done some testing on the bench with a clear cover. I don't remember the speed, but at some point all the lube ends up in the axle tubes. He said his was faster with more lube. At that time I added the other qt of lube. To my surprise I picked up almost 1/2 MPH there at Indy. Kept that gain after returning home. You may not believe it, but might want to test it for yourself. An extremely low HP car may see something different, but if it doesn't run quicker low on lube, why do it? Your results may vary. LOL
Btw, I use Royal Purple synthetic gear lube. Never a problem.