I'm changing the rear axle lube, and I have a question concerning the fluid level. The owner's manual lists the level as 1/4" below the filll plug +/-1/4",which would allow a fluid level up to the fill plug. But, the cover is engraved with a mark indicating the fluid level approximately 5/8" below the fill plug. I have some rear avle whine, and I'm tempted to fill to the plug. What level have you used?