when I bought the Breakaway I knew the rear axle had a small leak in the cover gasket, there'd be a small amount of gear lube under the axle wherever I parked for any length of time.

No big deal I'd just top it off and replace the gasket when I have the extra time. I noticed after I filled the gear box to the level just below fill plug, the axle would blow some gear lube out of the tube vent.

I got around to changing my gear lube, drained lube, pulled cover and noticed the original fill hole had been welded shut and a new fill hole was added 2" higher on the cover. Who ever did the work did a nice clean job. However the new level of fill looks to be too high, I measured the height from floor and it measured real close to the top of axle tube, allowing for the thickness of the tube. The old fill level is about center of the axle tube.

My question is which is right? I know low gear lube level is not good but than so is to much gear lube. I don't want the gear oil foaming and causing problems. I've only worked on a few axle's in my time and all of those fill level's would top off just above the axle tube level. But they were not a huge truck axle my Chassis data plate says mine is a Dana 80.

I sealed my axle cover with Permatex RTV refilled axle with 5 quarts of Valvoline semi synthetic 80W-90 gear lube and at that level it is about the height of the old plug. I could still add a few more to get it up to the new plug level.

Any thoughts?

When I got the Mag HyTech cover, the rep suggested the level be ~½" above the axle tube, so the bearings get a constant supply. Because the cover has to be inverted for a pusher, I made a small brass dipstick to check the level.

Well that explains everything! I'll go buy more gear lube.

Thanks Rusty!