Diff Covers

[Deleted User 38384]

The rear M220 on my '22 Willys does not have a drain plug. ?

See so I thought the same thing.... I changed my diff oil at 30,000 mi, and about 3,000 mi later I realized I do in fact have one.

Wish I knew that when I did the oil change, would have save me the trouble of yanking off the whole diff cover in the front and rear. Though probably good I did the first time around.

Curious what build month yours is?
I think I've heard they started not having the plugs sometime in '22. Mine was built in June.

So some of the early EcoDiesels and rubicons had a drain plug on the front differential if I remember right, on the bottom of the differential housing. Problem was it gets scuffed up and either knocked out or destroyed so you can't take it out. I think that's why they started removing them. However the rear differential has always been on driver side of the housing, just forward of the rear diff cover.

Mine was built in August of 2021. So you should have one on there. Be interesting to see if you didn't though.

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[jadmt]

Do any of you have the bottom ridge on the rear diff like on my 2024? It looks like that ridge could easily get caught up on a rock versus sliding over it.

yup mine is like that on my 2024 and it is a terrible design.

 

[Tncdrew]

Mine was built in January 2024.

Huh? Am I missing something? I thought above you said it was a '22

 

[Jtphoto]

Huh? Am I missing something? I thought above you said it was a '22

Sorry typo January 2022. I’ll edit my post.

 

[Flip]

I recently changed my axle fluids, 2023 Sport no drain plug. I bought a little hand pump, it worked out great.

https://www.harborfreight.com/multi-use-transfer-pump-63144.html

 

[Jtphoto]

That being said, I usually like to pull the cover and inspect gears once a year so to me it doesn’t matter much.
The JL also has neoprene gaskets so it’s an easy process.

 

[Flip]

That being said, I usually like to pull the cover and inspect gears once a year so to me it doesn’t matter much.
The JL also has neoprene gaskets so it’s an easy process.

Do you think it's OK if I remove the covers every other change?

 

[Jtphoto]

Do you think it's OK if I remove the covers every other change?

That depends on how many times you decide on changing the oil. Usually diff oil only needs to be changed once a year if that. Unless of course you put on a lot of miles or suspect you got water in the diffs. Changing oil never hurts so even pumping out the old oil and refilling even second time is better then not doing it at all.

 

[gsbrockman]

That being said, I usually like to pull the cover and inspect gears once a year so to me it doesn’t matter much.
The JL also has neoprene gaskets so it’s an easy process.

My 2014 RAM 3500 Crew Cab DRW H/O was equipped with AAM axles. The rear was an 11.8” / 300mm and servicing was a breeze on both the front and rear axles.

Given the ease of servicing with the reusable gaskets, I’d go that way every time.

 

[toothirtyj]

Good luck trying to get an answer. I’ve called and emailed everyone. The company must be entirely B2B, because I just can’t get customer service. I assume they are like most others with two plugs. The bottom one is for standard pinion angles and the top is for more extreme angles.

So if you have a standard pinion angle and you fill it to the upper hole is there any issues or disadvantages to doing this do you know?

I think filling to the top would add too much oil if you are a standard angle. In all honesty, though, that’s just an educated guess because I’ve been unable to confirm.

edit: if you fill it with too much oil it can affect how the oils moves around the ring. I've always heard overfilling a little can be worse than under filling a little, but I have no basis for knowing if that's true. I just try and follow the manufacturer's directions as I assume they know more than I do about their stuff. ?

What's up with the two plug setup?

The lower ones not low enough to use as a drain plug, so why have two?

Take my advice and DO NOT overfill the differential because it will result in a pinion seal leak. I added these covers to my '21 Willys while I was doing a 500 mile gear oil change after my re-gear. At that time, thinking the extra hole was for more capacity, I filled to the bottom of the top hole.

7000 miles later the pinion seal began leaking during a vacation to the Outer Banks in North Carolina. Not only did it put a damper on beach activities but I also had to limp the Jeep home to Indiana, stopping every hundred miles or so to add gear oil.

After researching, my understanding is the top plug is simply a better location to add gear oil and to make it easier to identify when the level is up to the bottom plug.

I also read where some stated the top hole was to be used when the differential is completely dry (such as initial assembly after a complete tear down) for the first fill up. However that doesn't make much sense since the stock cover only has the one hole.

More harm than good will be done from overfilling and I have first hand experience.

 

[Pareto Offroad]

Take my advice and DO NOT overfill the differential because it will result in a pinion seal leak. I added these covers to my '21 Willys while I was doing a 500 mile gear oil change after my re-gear. At that time, thinking the extra hole was for more capacity, I filled to the bottom of the top hole.

7000 miles later the pinion seal began leaking during a vacation to the Outer Banks in North Carolina. Not only did it put a damper on beach activities but I also had to limp the Jeep home to Indiana, stopping every hundred miles or so to add gear oil.

After researching, my understanding is the top plug is simply a better location to add gear oil and to make it easier to identify when the level is up to the bottom plug.

I also read where some stated the top hole was to be used when the differential is completely dry (such as initial assembly after a complete tear down) for the first fill up. However that doesn't make much sense since the stock cover only has the one hole.

More harm than good will be done from overfilling and I have first hand experience.

Thank you for sharing this! In your research, did it seem the capacities were the same?

I was going to flip the stock unit over and fill with water to the edge then do the same for the new one. I’d measure both and then the difference would be the change in capacity.

 

[Vatdevil]

Wondering if anyone has experience with these?

Magnet and level stick are nice, can tell if water seeped in. Stout, took a few hits with minimal damage.

 

[Jtphoto]

The fill hole on the stock cover matches with the lower hole on the Dana/spicer cover.

 

[toothirtyj]

Thank you for sharing this! In your research, did it seem the capacities were the same?

I was going to flip the stock unit over and fill with water to the edge then do the same for the new one. I’d measure both and then the difference would be the change in capacity.

It did seem they were the same but in a very unscientific way. The rear capacity is "3.06 pts" and I was using Valvoline gear oil which came in bags of quarts.

I think your water experiment could be very interesting but at the end of the day, I will continued to only fill to the bottom hole.

 

[JPAloha]

Wondering if anyone has experience with these?

I’ve had those on front and rear, since mine was about a year old. Had them on my previous JKR also.
Well made, well engineered. The drain plug, magnet and dipstick are all very handy to have.

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