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Bombproof Your Dana Diff: Spicer Performance Differential Cover Installation

  • Writer: Muddy Ruttzz
    Muddy Ruttzz
  • Oct 26
  • 7 min read

Why the Differential Cover is Your Jeep's First and Most Important Mod


If you own a Jeep Gladiator or Wrangler and you’re hitting the trails—especially the rocky terrain we have right here in Las Cruces, New Mexico—the single most important modification you can make is an upgraded differential cover.


No, this video/post isn't sponsored—I bought all this gear with my own hard-earned money!


The factory cover is thin stamped steel, and it offers about as much protection as a wet paper towel against a sharp rock. A busted differential on the trail can end your adventure fast and leave you with a massive repair bill. That's why installing a heavy-duty, cast iron cover is a non-negotiable step for any serious off-roader. It’s an easy, high-value DIY project that offers serious protection for your rig.


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Getting Familiar with the Dana/Spicer Differential Cover


There are a lot of great covers out there, but today we’re talking about the Dana/Spicer Advantek Performance Front Differential Cover (Part #10044799). This part fits the Dana 44 M210 axles found on the Jeep Gladiator (JT) and the Jeep JL Wrangler.

I chose the Dana/Spicer Differential Cover for a few simple reasons: it’s reasonably priced, and who knows your axle better than the guys who built it?


Person in gloves holds a stamped steel diff cover in a workshop. Text reads "THE OEM DIFF COVER IS STAMPED STEEL." Bike and tools visible.
Stamped Steel Is Great For A Pavement Princess But You Need More Protection When Heading Off-Road


Gloved hands reach for a black diff cover on a workbench with bolts in a metal tray and a box labeled Reinzosil. Text: Included in the box.
Everything You Need Except Fluid Is Included With The Diff Cover - Bolts & RTV

The Key Features of the Spicer Advantek Cover


  1. Bombproof Material: It's made from thick Nodular Iron, which is exponentially stronger than the stock stamped steel.

  2. Protection & Cooling: The design includes fins that not only add strength and provide a bit of cooling but also act as integrated sliders to prevent you from getting hung up on rocks. They also protect the bolt heads from being sheared off.

  3. Dual Fill Holes: You’ll notice two fill holes. I'll be using the bottom one. The top hole is primarily for high-pinion angle driveshafts or when filling a completely dry axle assembly


Person in plaid shirt and gloves holding textured metal object with fins. Text reads "Fins add strength and cooling" and "Bottom fins act as sliders."
The innovative design of the Spicer performance diff cover, showcasing fins that enhance strength and cooling, with bottom fins also doubling as sliders.

How Do You Install The Spicer Diff Cover? I'll Show You


I'm lucky that I've already installed a 2-inch lift on this Gladiator, giving me plenty of elbow room underneath. This job is a piece of cake for a retired sheet metal worker like me, and it will be for you too.

  1. Loosen the bolts on the OEM cover to let the old differential fluid drain out into a pan.

  2. Once the fluid is out, remove the rest of the bolts and take the old cover off.

  3. You'll see the OEM cover uses a reusable gasket. The new Spicer cover does not use this—we're ditching it for RTV sealant.


Tools on a workbench, including wrenches and a red drill. Text reads "DIFF COVER BOLTS ARE 10MM" and "Only A Few Simple Tools Required."
10 MM Sockets, Brake Clean, Rags are about all you need to to install the Spicer Performance Diff Cover to make a huge upgrade that protects your expensive differential gears.


Gloved hands remove a differential cover under a car. Text reads "REMOVING THE OEM DIFF COVER DRAINS FLUID" and "No Drain Hole On Differential."
There is no drain hole on the diff, draining fluid requires removing the cover. This is first step in the diff install process.

Gloved hand holds reusable gasket near a car differential. Text reads: "OEM cover uses re-usable gasket." Dusty metal parts in background.
OEM diff cover uses a reusable gasket to make diff fluid changes easier. Installation of the Spicer Performance Diff Cover uses only RTV and Reinzosil Universal RTV is the recommended product.

Prepping the Gasket Flange: Make it Smooth as Silk


This is the most critical step that separates a rushed job from a pro-level install. The surface on the axle housing where the cover bolts up is called the Gasket Flange or Mating Surface.

  • Cleanliness is Key: Scrape off any old gasket material or crud.

  • Smooth it Out: If you see any paint or burrs, smooth them out. The area you really care about is the part of the flange inside the bolt holes. This surface needs to be absolutely smooth as silk to ensure a perfect seal.


Close-up of a differential with a blue-gloved hand pointing to gasket flange. Text: "Flange must be cleaned prior" and "Gasket Flange."
There was some paint I had to smooth out on my diff but for the most part it was clean. A little careful scraping that did not scratch or gouge the surface and Brake Clean to remove any grease or oil residue that would interfere with the Reinzosil RTV creating a seal.

Prepping the New Cover and Applying Reinzosil RTV


  1. Degrease: Hit the flange of the new diff cover with some Brake Clean to degrease it. This is a must!

  2. Apply the Sealant: Reinzosil is amazing stuff that replaces countless other silicones, but it stinks and the warnings are real! Use it in a well-ventilated area (like my new garage studio!) and avoid skin contact.

  3. The Bead: Apply a nice, consistent bead of RTV around the inside of the bolt holes on the new cover's flange. Do not spread it around or go outside the bolt holes.

  4. Work Quickly (but Carefully!): You have about 5 to 15 minutes before the Reinzosil starts to skin over.


Mechanic with blue gloves assembling a car part in a garage. Tools, lubricant, and cleaning supplies on table. Jeep visible in background.
The new bolts that are supplied with the Spicer Performance Diff Cover are not long enough to hold the cover on if the reusable gasket is used. After cleaning up flange/mating surface of the new cover we are ready to install the RTV.
Tube of Reinzosil RTV gasket maker on metal floor. Mechanic applies product in workshop. Text reads: "Reinzosil RTV forms the only gasket needed."
Reinzosil is a kind of miracle universal RTV that has a multitude of uses. (See link below for more information.

More information on Reinzosil Here: https://victorreinz.us/products/reinzosil-rtv-silicone



Person applies sealant to a metal surface in a workshop. Text above reads: "Reinzsoil is applied on inside edge of mating surface only." Blue gloves and tools visible.
These are "Dry" Bolts on the Spicer Perfornance Diff Cover and do not require sealant around them. Apply the Reinzosil only to the inside edge of the cover.

Bolt Up and Torque Specs

I had everything lined up to prevent any delay.

  1. Careful Placement: Gently place the new cover onto the axle housing. Try to move it as little as possible to give the RTV the best chance of sealing properly.

  2. Snug It Down: Snug all the bolts using an impact gun in a criss-cross pattern.

  3. Torque Time: Finish them off with a torque wrench. You only need 25 to 30 foot-pounds (ft-lbs) of torque. Don't overdo it!

Mechanic with blue gloves installs a car part. Text above: "5 minutes to install before Reinzosil dries, place carefully." Weathered vehicle surface visible.
You want the Reinzosil to stay where it will do the job so try to put the new cover in place and and get a couple bolts in it without "smearing" the RTV around.
Mechanic in blue gloves adjusts a bolt in an engine with a ratchet. Text advises torque and checking for leaks. Outdoor Adventure logo visible.
Tighten the bolts in a Criss-Cross pattern and be super careful not to over tighten. I got a comment from a viewer on my Youtube channel who advised hand tighten till they are snug and check for leaks.

The Waiting Game: Cure Time and Fluid Fill (Wait Time Till Fluid Fill)

That’s it for now—time to put the tools down. The Reinzosil needs time to cure:

  • Functional Seal: It needs 4–6 hours to reach a "functional seal," which means we absolutely cannot add the diff fluid until then.

  • Full Cure: A full cure takes 25 to 100 hours, depending on conditions. I’ll be back in the morning to add the fluid.


Adding the Fluid

I’m a big fan of AMSOIL Differential Fluid. It’s a great product, made in the USA, and it already contains the limited-slip additives if your application requires them. I also love that it comes in these handy pouches that make pouring it into the diff filler hole a breeze.

  • Fill Point: Use the bottom fill hole on the new Spicer cover and fill it up until the fluid level is just slightly below the fill hole opening.


Blue-gloved hands use a socket wrench on a metal part with bolts. Text reads: "3/8 Socket Wrench fits Fill Holes" with details. Muddy Ruttzz logo.
2 holes are better than 1 when it comes to Diff Covers. If you have a high pinion angle or brand new dry axle use the top hole. For most the bottom hole is used.

Gloved hands refill a vehicle's gear with AMSOIL Severe Gear lubricant in a flexible pouch. Text reads: "I use AMSOIL for all my fluids.”
Great American made product. Amsoil is packaged in these flexible pouches that make it easy to reach the fill hole without needing a messy fluid transfer pump.


Conclusion

Now your Jeep’s front driveline is protected by a genuine, bombproof Dana/Spicer Differential Cover. You’ve traded that flimsy stock piece for a nodular iron shield, and you did it all yourself right here in your garage. Not only did you save money, but you learned a new skill and increased your confidence for the next trail challenge! That’s what DIY off-roading is all about.



Call to Action

If this guide helped you conquer your diff cover installation, let me know in the comments!

Ready for your next project? Browse the MuddyRuttzz.com blog for more DIY maintenance and modification articles. And, of course, be sure to head over to the Muddy Ruttzz YouTube Channel and subscribe—you can watch the full video version of this install and see how the new cover handles the New Mexico desert! See our Ouray Jeep Jamboree Adventure!



Merch Section


Support Muddy Ruttzz in Producing Quality Content. Use My Links. I will get a small commission when you do. (No extra cost to you.) Does not matter if you purchase the linked product I get credit for anything you purchase within 24 hours. Thanks!


Amazon Shopping


✅ - Spicer Performance Front Diff Cover Wrangler JL & Gladiator JT - https://amzn.to/4ocAUgm (Amazon)

✅ -Spicer Performance Rear Diff Cover Wrangler JL & Gladiator JT- https://amzn.to/431vEng (Amazon)

✅ - Reinzosil Universal RTV - https://amzn.to/4qyg3FS (Amazon)

✅ - Amsoil differential fluid 75w-85 - https://amzn.to/47jOb0J (Amazon)

✅ - Use This Link To Shop On Amazon (https://amzn.to/4hinMDx)



✅ - Dana Performance Diff Cover Wrangler JL Gladiator JT - https://ebay.us/DlpfWm

✅ - Amasoil 75-90 Differential Fluid - https://ebay.us/jW9jka (eBay)

✅ - Reinzosil Universal RTV - https://ebay.us/dv3vWr (eBay)



Smiling man sitting in car holding on to steering wheel. Car is yellow color and door is open. Grass is visible on the other side of the car. There is also add for ebay Motors.
Click Here To Find Parts On Ebay Motors!


✅ - Zarges Aluminum Cases - Best Made Overlanding Storage Cases. When you require the best protection for you gear. Bear Resitant available. (Zarges)


Stacked Zarges Aluminum Cases sitting next to a Jeep Gladiator.
Zarges Aluminum Cases

✅ - MERCH Availabe on Spreadshop - Awesome Original Design Shirts and Merch - Muddy Ruttzz Clothing.

Click Here to See my Zarges Blogpost.


As a Amazon Affiliate and Ebay Partner I receive a commission if you use my links to make a qualifying purchase. It does not raise the price you pay.






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