Changing my stock diff covers to ARB covers on my 2010 JKU Rubi....I have the facrory specs on the amounts of gear oil for "stock" covers....can someone tell me at what actual level the oil should be, say relative to the bottom of the axle tubes???? the ARB covers have a "dipstick" that I would like to mark correctly....Thanks

 

Look at the old covers, the bottom of the fill hole is the "Full" mark.

 

The fill amount would be the same as factory spec. Everyone's full mark with a modified Jeep is going to be different, depends on height of lift. So the full line on the dipstick is going to be different. Best way to be sure you have the correct amount of gear oil is to measure it going in and then make a mark for future reference.

Front Differential Capacity:
2.7 pints (1.35 quarts)

Rear Differential Capacity:
4.75 pints (2.375 quarts)

 

Putting a number on the quantity is pointless.

Go by the great picture above to ensure there is enough oil to bring it above the bottom of the axle tube. This will allow the oil to get to the outer axle bearings.
Same level applies to the front, too.

 

That's not a good blanket statement to make. (A little overfill is not a problem.)
Overfilling can cause the oil to spew out the overflow at the least, and can cause the oil to foam at the worst, which is not good for the gears and bearings.

 

What do you mean by the height of lift? Does it matter? And if so, how do you determine what the correct amount of fluid should be in a X" lift.

 

The higher the lift, the more the axle may rotate, making the stock fill plug lower.

To ensure the proper fill for almost any situation, see the photograph above, and the post right after it.

 

From what I remember, the installation instructions clearly note that the dipstick should be "marked" for the proper oil level. The covers take more oil than OEM covers. So, for my understanding....fill it little by little, put the dipstick back in (without tightening it), check the level, fill as needed again, and confirm the level again.

That is from ARB directly. They also mentioned to make sure to not overfill as the oil "making a mess" is the least of your worries, it can cause a lot worse damage.

 

Now I understand. Not so much more fluid as opposed to different level when using stock cover.

 

It's good that they include the dip stick, clearly marked.

But the owner should also know why the oil needs to be at a certain level, so he can double check what the dip stick is indicating on his particular vehicle. Being a little above the bottom of the inside of the axle tube takes precedence over a quantity number, or the mark on a dip stick.