so i've read the write-ups and i've changed diff fluid on several vehicles before, but this is the first time on my rubi. when i pulled the front fill plug (not the drain plug) oil came pouring out. wasn't a massive amount, but it was a fairly decent flow. i just got it all put back together and went to put oil in, but after 1qt, it's now coming out of the fill hole. i know that's usually the stopping point when you fill with a stock cover, but i'm also pretty sure that the front takes a bit more than 1qt. should i:
1. leave as-is
2. park on an incline somewhere and add a bit
3. run it for a while the way it is then add more tomorrow

im going to go do the rear now. hopefully it's a bit easier without the tie rod or air dam (or what WAS my air dam before i ripped it off ) in the way. i might drop 1 side of the track bar too to make it a bit easier. thanks in advance, any help is appreciated.

 

I parked on ramps, then lifted one end of the axle, to get in what came out.
It was something like 15 ounces above the fill hole. Ended up with near the amount the FSM says is what goes in.
I did this because it is a high pinion, and wanted to make sure the pinion bearings get the oil they need.
I have no oil leaking, and none coming out the breather tube.

Here are the factory differential capacities for the JK:

FRONT AXLE ± .03 L (1 oz.)
186 FBI (Model 30) 1.0 L (1.05 qts)
216 FBI (Model 44) 1.3 L (1.35 qts)

REAR AXLE ± .03 L (1 oz.)
198 RBI (Model 35) 1.83 L (1.9 qts)
226 RBI (Model 44) 2.25 L (2.4 qts)

Actual amounts from factory on my vehicle:
Front Dana 44: 44oz (15oz above bottom of fill hole) (1.4 qts)
Rear Dana 44: 72oz (slightly above bottom of fill hole) (2.25 qts)

 

ronjenx, this is interesting. I have a 09 Unlimited Sahara and just put synthetic in today. In the front I put 2oz shy of a full quart. It would run out faster than I could get it in.

In the rear I put exactly 2 quarts, to do this I held my thumb over most of the fill hole to effectively raise the level. I had to be real quick getting the plug in place before losing oil. Easy on the back side.

So are you saying that I do not have a enough in the front, or rear, even though is flows out while parked on level ground?

 

Not saying you don't have enough. After all, the bottom of the fill hole is the right hight on the stock covers.
I was just explaining why I refilled with the "correct" amount, even though it was 15 ounces over the bottom of the fill hole on the front.
The published amount is probably correct for a regular Dana 44.
With the locker installed, which takes up some space, the published amount will be a little higher than the bottom of the fill hole.

 

Park on a level surface and fill it to the bottom of the fill hole

 

Thanks guys, I am old school and have always just filled till it started flowing out. I just wanted to make sure that was still a good philosophy. Never know how things are changed in new vehicles. I was just a little confused by filling it up past the hole...

 

the rear is now done and i did the same thing as MoridinTX for the rear. i was almost done the 2nd qt when it started flowing out so i covered most of the hole with my thumb and finished it off. what i'm looking at is 1qt front and 2qt in the rear. and btw, dropping the axle side of the track bar helped a ton in being able to reach everything better. just a little tip for any considering doing this in the future

 

It does seem that oil will come out of the fill hole before reaching the stated amount. I used the unscientific "splash and dash" technique. Upon filling until it was starting to seep out of the hole, I gave it another good burst and intalled the plug immediately. Should be close(r) to correct amount.

 

I think the extra oil is not being drained out when you remove the plug. In most axles there is a depression in the bottom of the housing that doesn't get removed with the drain plug. There is easily several ounces in there.

 

In most cases yes, but I pulled my covers out and cleaned out the interior My worry is that I don't have enough lube in there.... I just don't understand the discrepancy between the factory capacity listing and what I can actually get in there