Gear Lube Level

[njk53]

Does the level of gear lube in a rear end have any effect on performance? If the gear lube level is filled to the bottom of the fill plug, can or does windage come into play creating performance losses?
If so, on a 12 bolt Chevrolet how much lube should be used and/or where should the level be relative to the ring and pinion?

[HandOverFist]

Don't know if you will get a definitive answer on this...I've always ran 2 quarts in a 12-bolt without any bearing failures.

http://classracer.com/classforum/sho...gear+oil+level

[Dragsinger]

Nelson,

From personal experience with 12 bolt, 1.5 quarts running mid 9's at 3100 pounds. No problems using Lucas 80/90 [Lucas #10043] conventional gear oil.

This is also what I will do with my upcoming build of the Super 10

[Mike Semeniuk]

FWIW - I have always run 1 - 1.25 quart of 80-90 synthetic Lucas or Valvoline. If the rear end if completely dry - I use 1.5 qt. There was a thread on here a while back - and the opinions and experiences varied. The only other thing, I remember reading on the MW site years ago that they didn't favour synthetic. When I used dinosaur oil, I had no different experience, except cold mornings.

[Lou Jeffery]

In a Drag car that is only run for short distance you can safely get away with very little amounts of gear oil. Keep in mind the differential bearings and axle bearings rotate at a relatively low rpm. The pinion bearings rotate at close to engine speed at the finish line but they are force fed gear oil by the pumping action of the ring gear. So as long as you have enough oil for the ring gear to dig into you will not have problems. My 8.8 Ford axles that are very similar to a 12 bolt GM use no more 1.5 quarts.

[ghost]

In drag only, with spool 10 sec car, I run 1.5 motor oil 10w40. Next step ATF oil. Reason... less difference between the run (cold) and (hot). Never broke the gear.