That was my initial thought as well. But attempting to fill it to the level of the hole took more than the stated capacity, to the point that I stopped out of concern that it might be overfilled. Here’s a picture of the hole height. It’s above the center line of the axle tube. Are the OEM fill holes that high?
I really don’t think you can over fill. The diff should have a breather hose if temps cause the liquid to expand. Bottom line is you want all those gears completely submerged to reduce wear.That was my initial thought as well. But attempting to fill it to the level of the hole took more than the stated capacity, to the point that I stopped out of concern that it might be overfilled. Here’s a picture of the hole height. It’s above the center line of the axle tube. Are the OEM fill holes that high?
That's a question best answered by the manufacturer. You could then vet their reply through a CDJR Service Dept. of your choosing.
I’m guessing you’ve never spoken to a service writer, service technician, or service manager at a dealership? First they’re going to ask me for my VIN. Then they’ll want to flash my ECU. Then they’ll give me a part number for an OEM diff cover and gasket, which will be obscenely priced and out of stock with no ETA. Then they’ll inform me that non OEM parts installation or DIY labor will void my warranty. Then they’ll maybe be motivated enough to look up the fluid capacity in the manual and quote it to me. Which I’ve already exceeded and it’s still not full to the fill hole. Then I’ll be right back here asking you guys in case anyone with this cover knows the answer for sure.
See, that’s my concern. I’m not sure if “more is better” in this case, that’s why I ask. Will filling it too high not cause issue with seals?
Ok, ok... Did you get everything out of your system now?
Good advice. I should have called MC from the start.Ok, ok... Did you get everything out of your system now?
I've spoken to service writers many times. I'm related to one (a first cousin). Sure, there's the potential for them to brush you off, but that's not guaranteed to occur, and you may get a nugget of genuine advice out of them before taking your leave.
I'll mention again that your inquiry might get a fair hearing at the manufacturer, if you ask them first, before considering a phone call or visit to a Jeep dealer. Just a thought.
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Do I think differentials can be overfilled? Absolutely, I do. So it's a subject that I'd chase down in a particular order, with the related vehicle forum being #3 or so in the batting order.
I think MC will have the best answer on that, for sure. Their cover, their changes to fill volume, their fill hole placement.
“The bottom of the plug hole is the maximum fill line, so when oil starts dripping out, you're finished.”
Thanks. Now that we have it I am fine with them but I don't really use them getting in and out. My Wife and kids do and I'm sure there is more flex than a steel design but I like how far the stick out which helps keep rocks off the hinges and fenders. Ours is mainly for street/beach.
I had a WK with a 4” lift that slightly modified the angle of the front diff. The front gears went bad, so the dealership replaced the entire front axle under warranty; within 10 miles of installation the axle went went bad. Hmmm, must have been a manufacturing defect, so they replaced entire assembly AGAIN and the same thing happened. Turns out the axle assembly is filled with oil at the factory and the slightly different angle introduced by the lift prevented oil from getting to the rear of the axle. They replaced the axle a third time and topped up the oil and everything was fine.
There are bolts at the base of the a-pillars that are candidates, but the magnetic base of the flag would need to be pretty small since the bolts are slightly recessed.
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