There are write-ups with all the necessary amounts on project-jk. It doesn't hurt to run extra, you just risk having it come out your breathers and making a mess. A lot of people run theirs filled high. I personally use Mobile1 - a good synthetic thats middle of the road - better than stock, not as expensive as RP. You are correct about the additive, only LSD's need it.

 

I use Schaeffers Synthetic gear lube. i have been really impressed with it,but i do have to order it online but it is under 10 bucks a quart

 

Where did you find the Schaeffers stuff online? I've looked and didn't find anything, and the closest dealer to me is atleast an hour away. I've always been a big fan of their stuff.

 

Oh, and just incase some don't know, most synthetic gear oils you can get today, have the limited slip additive in it already. It should say some where on the bottle.

 

i got it from ...speedpartz.com
they have it for $11.25 a quart.I thought i paid just under 10 bucks a quart for it but i must of been mistaken

 

Most gear oil is in the 90 weight range. when you couple that with a 360 degree ring gear with teeth on it that actually PICK UP the gear oil, you can see that it's gonna go every frikkin where in that case, includin all over the pinion. Even if the pinion is pointing nose down, so the gear oil will run out of it at rest, while the Jeep is in motion, it and it's bearings are gettin drenched.

...and as for the discussion on the fill level. This oughtta be kinda simple. If you have the stock covers. Just go by what the owner's manual says. I've found sometimes you have to disregard the fill hole. You may have to jack one side of the axle up to get the required amount in. Now, if you have aftermarket covers, they SHOULD come with some kinda deestruckshuns tellin you how much or how to fill. Since they probably have a different interior profile than stock, that may change the amount the axle holds. Truthfully, if about the boottom third of the ring gear is submerged, that's about all you need. Since the axle housing ain't made outta that clear cast iron yet, that's kinda hard to tell though.

 

On the rear axle, the outer axle shaft bearings are lubicated with oil from the differential housing. Whatever amount of oil you decide to have, it must be higher than the bottom of the axle tubes. This will ensure adequate oil to the outer bearings. The front axle may be the same, except it would be to keep the shaft seals wet.

 

I just installed Riddlers last weekend. Just like the posting on project-jk write-up comments, my front 30 took just shy of 1.5 bottles (came to the fill-hole) and the rear 44 took just shy of 2.5 bottles (just a smidgeon under the fill-hole). I'm running Valvoline 75W-90 Synthetic that I picked up from Napa. It was about $11/bottle. I checked PepBoys for Royal Purple but they were out. So far, so good.

 

I love beating dead horses....

SO... for my jeep

front 44 - 2 quarts
rear 44 - 2.5 quarts

Correct?????

 

So the project JK write-up says:

Front Differential Capacity:
2.7 pints (1.35 quarts)

Rear Differential Capacity:
4.75 pints (2.375 quarts)

Is this assuming the front is a D30? Are these amounts applicable to the front D44? Does the rear hold that much more fluid? I have ARB cover and no longer have my originals so an exact amount on the front would be good to know. Strangely the owners manual gives no amount.