Aftermarket Diff Cover Fill Level

[Tarmijo94]

Hey everyone.

Just finished up my install of my aussie and chromoly shafts in my front axle (Dana 30) this morning. The PO had put an G2 diff cover on (linked below) in which the fill plug is quite a bit higher than the stock cover. First, is than an okay cover to keep (I know some covers have issues with oil distribution) and what should the fluid level be inside the diff. I am able to stick an allen key in as a makeshift dipstick, but I'm just not sure where the ideal fluid level should sit. There currently about 1.5 quarts and the fluid is just about at the bottom of the axle tube.

https://www.4wheelparts.com/p/g2-ax...-30-raw-aluminum-40-2031al/_/R-FCNB-40-2031AL
I read someone on a different site state that it should be halfway up the tube, but I also know having too much is quite the messy mistake.

 

[Rubicon88]

Stick your finger in hole. Do you feel the lube? If so...you've got enough.

This is completely G rated i assure you.

 

[The Real Lxxtsy]

Once the oil overflows out of the fill hole , that's when I know I'm good on oil.

 

[Tarmijo94]

you've got enough.

Once the oil overflows

Gotcha. Ill go throw some more in it in a bit. I was hesititant to add up to the higher fill hole and have it leak out of the seals

 

[Chris]

Stick your finger in hole. Do you feel the lube? If so...you've got enough.

This is completely G rated i assure you.

 

[hosejockey61]

IMHO stick with the manufactures recommendation, in this case 1.2l for a Dana 30. You CAN have too much gear oil in a diff. An aftermarket diff cover doesn't make it ok to add more simply because the fill plug is locate higher.

Another example would be a rear Dana 44 that has a greater pinion angle when installing a SYE. The higher fill plug helps with getting the correct amount in since it is tilted back. Sometimes even with a higher plug you still might not be able to get enough in. The work around to make sure you are getting the full 1.9l in is to add the rest through the breather tube connection.

YMMV

 

[Tarmijo94]

You CAN have too much gear oil in a diff. An aftermarket diff cover doesn't make it ok to add more simply because the fill plug is locate higher

Thats the root of the confusion. I know not all cover shapes are created equal either, so was trying to figure out if there was a level relative to something in the diff as opposed to fill plug which is higher. My rear cover is higher too, but i have the pinion rotated up, so that one doesnt worry me as much, and was filled by a shop. This is my first time filling it myself.

 

[toximus]

1) Ask the manufacture.
2) Fill by volume, not by level.

 

[LONGJP2]

Thats the root of the confusion. I know not all cover shapes are created equal either, so was trying to figure out if there was a level relative to something in the diff as opposed to fill plug which is higher. My rear cover is higher too, but i have the pinion rotated up, so that one doesnt worry me as much, and was filled by a shop. This is my first time filling it myself.

I'm with you about fluid level can't be by volume once you change the shape/size of the cover or the angle of the diff.

I usually base it on where the fluid level would be using a stock cover at stock height. That's usually level with the bottom of the ID of the tube. You wouldn't want it higher than the seals. Then make a dipstick for that level using the new fill hole.
However, I don't know how that affects the pinion when it's angled up and higher than the oil level.

 

[jjvw]

I fill mine through the vent tube to the recommended volume. On the rear with the ARB, bigger ring gear, and raised pinon, this is too much fluid. It takes a couple weeks of daily driving for the diff to self correct and spit the extra fluid out of the vent.

I don't know what the correct volume is anymore, but the Jeep does.

 

[Tarmijo94]

spit the extra fluid out of the vent.

Does this hurt anything besides make a mess? Still trying to decide if I'm gonna throw the last half quart in or not

 

[jjvw]

Does this hurt anything besides make a mess? Still trying to decide if I'm gonna throw the last half quart in or not

It will hurt your linens if you store them under the Jeep. Don't do that.

 

[Tarmijo94]

Well damn, guess ill find a new place for those

 

[Rubicon88]

Does this hurt anything besides make a mess? Still trying to decide if I'm gonna throw the last half quart in or not

You're stressing about this way too much. Like you could be using this time trying to decide between swapping in a 360 dodge v8 or swapping in a 5.9 Mopar

Seriously though...

If you can feel lube you're good to go!! I promise you 101 percent.

 

[jjvw]

You're stressing about this way too much. Like you could be using this time trying to decide between swapping in a 360 dodge v8 or swapping in a 5.9 Mopar

Seriously though...

If you can feel lube you're good to go!! I promise you 101 percent.

How do you account for the varying heights of fill holes on different covers? What about raised pinions that change the volume and the height of the fill hole?

 

[Rubicon88]

How do you account for the varying heights of fill holes on different covers? What about raised pinions that change the volume and the height of the fill hole?

I think I covered that.?.?.?

Stick your finger in the hole...can you feel lube? Pretty simple.

If I need to really specify here...
On his particular diff cover the fill hole is higher than most....if I stick my pinky finger in there and point it downward...well now...im about half way down the diff cover. If I get lube on the tip of my finger...perfect. Close fill plug, go wheeling.

The finger method works every time all the time.

 

[jjvw]

I think I covered that.?.?.?

Stick your finger in the hole...can you feel lube? Pretty simple.

If I need to really specify here...
On his particular diff cover the fill hole is higher than most....if I stick my pinky finger in there and point it downward...well now...im about half way down the diff cover. If I get lube on the tip of my finger...perfect. Close fill plug, go wheeling.

The finger method works every time all the time.

If I were to open my rear fill plug right now, fluid would drain out before I could stick my pinky in the hole.

 

[Rubicon88]

If I were to open my rear fill plug right now, fluid would drain out before I could stick my pinky in the hole.

Ok???
Then you have enough fluid.
If it didn't run out and you stuck your finger in there and felt fluid.....

You'd have enough fluid.

 

[jjvw]

Ok???
Then you have enough fluid.
If it didn't run out and you stuck your finger in there and felt fluid.....

You'd have enough fluid.

Whether or not it amounts to anything meaningful, I suspect yours are on the low side. I know there is enough in mine.