Put in 1.3 Quarts and you are good.

 

What I want to know is how do you check the level when doing an oil change?
With the D30 and 8.25 on my XJ with the factory covers I just make sure some dribbles out.
How do you that when the fill hole is higher?
From another thread on this forum concerning a Solid cover.

https://www.jeepforum.com/forum/f9/how-much-oil-solid-diff-cover-701013/

From Solid:

If it is going on a stock assembly, which it sounds like it is, just go by the manufacturers specifications. The higher fill plug on our covers allow for an added ease of filling, not for more oil. If you put too much in, you'll start spitting oil out of the tubes.

I read where some guy made a makeshift dipstick to check. LOL.
And would drain plug be to much to ask? MLOL.

 

What I want to know is how do you check the level when doing an oil change?

Zilliver just answered you above: fill in ~1.3 quarts like the owner's manual/ FSM states. Slight overfill is not an issue, but having way too much diff fluid will cause foaming and oil seeping through axle seals.

Like you mentioned, with stock diff covers you fill to the bottom of fill hole.

 

general rule from old school is 1/4 inch or so deep in the axletube which should be just under the axle seal and cover the bottom of the bearing in oil. another old school rule is 1/4 inch from the bottom of the tube housing. so pick you flavor and have at her, im not sure about Solid but if it increases the capacity the stock fill amount wont be enough :smile2:


- added - ya a dip stick from some coat hanger or such would work i made one for my ac pump when i turned its orientation

 

Now this is all making sense. It was overfilled. If you wanted to know, with a solid cover you can fit about 2.5 quarts before it comes out the fill hole. Thanks everyone.

 

Thank you for confirming what I already though.
If I were you I would get a piece of a metal coat hanger.
Bend it 90 or 180 degrees. Stick one end in there. See where the level ends up on it.
Keep cutting it until you get to a length that just barely shows gear oil on it.
High quality diff gear oil measuring device. LOL.
Just remember which end goes in the diff and which end does not. MLOL.

 

I understand what they are saying. If you ever had a slow weep or seep from the differential be it the pinion seal, diff cover, or tube seals, you get it the habit of checking the level in the diffs and topping up. On my first ZJ I would check and top off every time I changed the engine oil. Current ZJ has fully rebuilt axles w/ lube lockers and they don’t leak / weep a drop.

I have heard of people using a zip tie or Allen key to dip in the fill hole to check level with an aftermarket cover.

On the rear 8.8 there isn’t even a fill hole on the riddler cast steel cover I have. The fill hole is on the front side of the housing on top near the pinion. I actually had it too full for about a year and when I finally changed from Lucas full synthetic to the correct amount of AMSOIL severe gear gas mileage went up and it seemed to coast / accelerate easier.

 

This is a pretty good demonstrative and discussion on differential oil fill level.

 

Like I mentioned earlier, slight overfill isn't an issue, but severe overfill does cause foaming. Too low diff fluid level especially in a high pinion housing can and does cause outer pinion bearing fluid starvation.

As for loosing diff fluid, there needs to be a noticable drip from pinion seal or diff cover, or fluid oozing out of the axle tube(s) for a leak to be large enough to cause fluid level to drop fairly quickly.
At that point it certainly is worth checking fluid level, but the preferred method would be to fix the leak

 

Gotta fab a 1/2" thick clear polycarbonate diff cover