Front Dana 44 Fluid Capacity

Kenneth G Zinis

Kenneth G Zinis

TJ Enthusiast
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Bethlehem, PA
Guys,

Just noticed fill hole on my factory '03 Rubi front diff cover is lower than on the rear cover, ~ 1". I see the part number on F&R factory covers are different too. Replaced stock with Metalcloaks and fill holes are same height, both F&R.

On refill each diff took 2 qts each so capacity appears unchanged from stock.

Anyone know why front hole is set lower? Will filling front to bottom of hole cause any issues? Should I follow the lower level from factory covers?

Thanks,

Ken
 
Rubicon Dana 44 (FRONT) - 1.375 quarts 75W-140 synthetic
Rubicon Dana 44 (REAR) - 2 quarts 75W-140 synthetic

Disregard the fill holes. Fill to the factory recommend volumes through the vent.
 
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Don't overfill your differentials unless you enjoy oil seal leaks.

Compare the old fill hole levels and new fill hole levels in relation to the axle tubes. Keep the fill level the same in relation to the axle tubes which almost always means using the factory recommended volume of gear oil. In fact, you should use the factory recommended volume unless the manufacturer of the differential cover specifically calls for a different amount. "High Fill" does not equate to "High Volume" unless so stated by the manufacturer.

Either fill through the fill hole or down the vent tube if your differential is at an angle where you can't get all the gear oil in without it leaking out the fill hole.
 
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Mr. Bills said:
Don't overfill your differentials unless you enjoy oil seal leaks.

Compare the old fill hole levels and new fill hole levels in relation to the axle tubes. Keep the fill level the same in relation to the axle tubes which almost always means using the factory recommended volume of gear oil. In fact, you should use the factory recommended volume unless the manufacturer of the differential cover specifically calls for a different amount. "High Fill" does not equate to "High Volume" unless so stated by the manufacturer.

Either fill through the fill hole or down the vent tube if your differential is at an angle where you can't get all the gear oil in without it leaking out the fill hole.
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I'm going with JJvw's volume, 1.375 qt, but I'll check and mark old level using your idea. I'm making a dip stick too, since I can't feel oil level through fill hole.
 
jjvw said:
Rubicon Dana 44 (FRONT) - 1.375 quarts 75W-140 synthetic
Rubicon Dana 44 (REAR) - 2 quarts 75W-140 synthetic

Disregard the fill holes. Fill to the factory recommend volumes through the vent.
Click to expand...
jjvw, can you tell me the source of the front diff volume of 1.375 qt? Thanks
 
Jerry Bransford said:
Absolutely no need for that, you simply fill it until it overflows. Diff consume no oil unless there's a leak.
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Jerry, I agree, my concern is the new Metalcloak front cover has hole ~ 1 " higher than factory cover, ie same as rear cover. The volume of new cover seems similar to factory cover, except for fill hole height
 
Jerry Bransford said:
Absolutely no need for that, you simply fill it until it overflows. . . .
Click to expand...

That tried and true technique works well for stock differential covers and mild suspension lifts but does not always work for high fill aftermarket differential covers or extreme pinion angles.
 
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The front diff can probably be happy at a wider range of fill levels than the rear. It has a lower fill hole because it only needs enough fluid to lubricate the gears and bearings in the pumpkin. The rear needs a higher level so that there is enough to run down the axle tubes and lubricate the bearings. The rear is probably a little less tolerant of differences in fill level...too little and the axle bearings could suffer, too much and some could get puked out the vent.
 
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Mr. Bills said:
Nope. Overfill the front differential and the oil pushes past the oil seals out the tubes and makes a mess.

Every. Freaking. Time. You. Drive.
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Maybe I should have said " a slightly wider range of fill levels...?"


Seems like you should be able to fill the front to the same level as the rear (lower/higher fill holes notwithstanding) without pushing oil out...

Not the case?
 
rouxbicon said:
The front diff can probably be happy at a wider range of fill levels than the rear. It has a lower fill hole because it only needs enough fluid to lubricate the gears and bearings in the pumpkin. The rear needs a higher level so that there is enough to run down the axle tubes and lubricate the bearings. The rear is probably a little less tolerant of differences in fill level...too little and the axle bearings could suffer, too much and some could get puked out the vent.
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rouxbicon, thanks for that insight, great explanation
 
I thought the general rule of thumb was the oil level should be right at the fill hole? I checked my 44 rear the other day and it was pretty much right below the fill hole. I thought that was good? Otherwise I’ll fill it up. Don’t wanna trash my rear
 
Joseph said:
I thought the general rule of thumb was the oil level should be right at the fill hole? I checked my 44 rear the other day and it was pretty much right below the fill hole. I thought that was good? Otherwise I’ll fill it up. Don’t wanna trash my rear
Click to expand...
If you have a lift or rotated the pinion up (tummy tuck) you need to put the factory amount through the vent tube instead of filling it up to the plug.
 
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