Differential Cover

[Dualsport650]

So I am a bit confused on which axles use the high plug and why. I thought until today that all covers for Dana 27 and 30 used the low fill port/plug. I recently picked up a used 30 cover not even knowing there was a difference. As I checked my two CJ5 's each one is different then the other. I guess perhaps one was changed or did Dana just use what ever cover was laying that day?

 

[Torxhead]

Right off hand I would think it would be better for lubrication when the axles are rotated to accommodate for a lifted suspension. When the axle is rotated, it does make it hard to lubricate the pinion seal.

 

[gert]

maybe you picked up a high pinion cover and they kept the fluid level higher to lube the pinion.

 

[Lumpy Grits]

Seals don't need lube. Bearings do, and the ring gear makes a great paddle wheel for this..
There are high pinion 30's out there and that is what the odd cover is for.
LG