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Modern 4x4’s are surprisingly capable. If you are looking to get out on the trails, you can have a lot of fun on the easier routes without spending a ton of money on upgrades.
Of course, we all know how that goes: A successful day of fun on the easy trails immediately leads to plans for tackling the tougher stuff and the mods to your ride necessary to make it happen. After all, nobody wants to be stuck on the “bunny slopes” forever.
And it’s definitely true that growing your skills and tackling the tougher trails is the way to continue upping the fun factor in off-roading. As the difficulty ramps up, it is a good idea to start thinking about a few intelligent mods to your ride to help with both durability and capability. If you are smart, you can create a great trail rig that will last for years without breaking the bank. That doesn’t mean giant light bars and 20-inch wheels. Instead, to increase the capability of your 4x4, the best first mods are usually a winch and larger tires (along with a lift if necessary).
That’s obvious, but just as important is considering the durability of your ride. Two of the best additions to help make sure you make it home when you begin upgrading your rig are axle armor and rock sliders. Here, we are taking steps to protect the axles on a Jeep Wrangler Unlimited with a pair of diff covers from B&M.
The idea here is to replace the stock, stamped-steel diff covers with heavy duty nodular-iron cast covers from B&M. With a 5/16-inch thick flange, the cast B&M cover does a good job of strengthening the entire axle structure, versus the stamped steel stock unit designed only to keep the gear oil from pouring out of the housing. Axle-housing flex can lead to accelerated gear wear and broken axles, so this is a very legitimate way to improve durability.
But there are additional benefits to this mod. Besides strengthening the overall structure of the axle housing, the B&M diff covers have a few additional features that are very cool. For instance, they integrate a dipstick into the fill port so you can easily and quickly check fluid levels and quality. This is important because if you are wheeling in creeks or mud bogs, water entrapment in the axle housing can be very damaging to your axles, ring and pinion, and lockers. With the B&M covers, you can quickly pull the dipstick and check for water or mud on it.
Also, both the dipstick and the drain plug have been fitted with magnetic tips to collect any metal fragments that might be floating in the gear oil. So not only do the magnets keep any metal out of your gears, but they also make it easy to spot any metal in your oils to help you diagnose any driveline issues before it can become a failure on the trail.
The Wrangler we’re upgrading is a 2012 Unlimited. It has been outfitted from the factory with the very common Dana 30 up front and a Dana 44 in the rear. We’re using B&M part numbers 12310 for the Dana 30 diff cover and 12312 for the Dana 44. Dana 30’s and 44’s have been used in a wide variety of vehicles over the years, and these diff covers should work with any of them. B&M also has a wide range of cast iron and aluminum covers for a huge range of vehicles. And best of all, they are all made right here in the USA.
For this swap we spent only approximately 30 minutes on each end of the Jeep doing the swaps. They are quick and easy to install and require only common hand tools. We even did it with the Jeep sitting flat on the ground. No lifts or even a jack necessary!
Here’s a look at the new covers we’re installing. On the left is the B&M diff cover for the Dana 30, which is up front on the Jeep Wrangler, and on the right is the cover for the Dana 44 out back. Notice the quality black powdercoat, the strengthening ribs, and the overall heft of both units. Also included are all-new stainless fasteners because the old bolts are too short with the thicker cast flanges on these new covers.
The Jeep already has a 3-inch lift and 35-inch tall tires, so access to the axles is pretty easy. We did ours with the Jeep sitting flat on the shop floor, and it was a piece of cake. But if you need to you can put your vehicle up on jackstands for easier access.
Let us begin by popping off the stock stamped steel cover. The Dana 44 has ten bolts around the perimeter.
Both the front and rear diffs have drain plugs in the housings (not the covers), but I prefer to simply pop the cover and let the fluid drain out that way. It really isn’t any messier, and besides saving a step, not pulling the plug means you eliminate the chance that it may leak after putting it back in. I usually leave the topmost bolt in the housing but loose so that when I pop the cover with a screwdriver it can’t fall into my catch pan and splash old gear oil all over me.
I use brake cleaner to help remove the loose gasket material and also clean the guts of the differential for inspection. Brake cleaner not only does a good job of removing oil and grime off of practically anything, but it also evaporates completely without leaving behind any residue. Just make sure to wipe down any excess and allow time for it to evaporate before sealing the diff back up and pouring in new gear oil.
There is no gasket sealing the diff cover. The factory simply used silicone to seal everything up. I scraped off the biggest remaining chunks and then used a Scotchbrite pad for final clean-up. Remember, the cleaner you get the mating surfaces between the housing and the diff cover, the more likely you are to get a leak-free seal. It isn’t shown here, but while scraping across the top of the housing, I crammed a paper towel into the opening to keep any silicone scrapings from getting into the housing.
Now is a great time to inspect the diff’s innards for any problems. Look for chips, cracks, heat discoloration and broken teeth.
Here’s a look at the underside of the B&M cast-iron diff cover. Despite being significantly thicker than the stock stamped-steel piece, the interior volume is the same so it will hold the same volume of gear oil.
The included dipstick isn’t marked for the oil level, so you will need to do that. One method is to set the oil diff cover beside the new unit from B&M and mark a horizontal line from the bottom of the drain plug across to the new housing. The method that worked best for me was to place the cover in a carpenter’s square so I knew everything was squared up and measure from the square to the bottom of the drain plug. Then I repeated the process on the B&M cover.
Here, you can see the new B&M cover in the same setup. I’ve already used a silver Sharpie to mark the spot we measured from the bottom of the drain plug on the stock cover to mark the proper gear-oil level. Next, I transferred this mark to the dipstick which has been laid on top of the cover.
To make the mark permanent, I simply scribed a line onto the dipstick with a triangle file.
Now you can see the setup from inside the cover. The dipstick is in place, and you can see the mark for optimum fluid level. The dipstick’s placement seems to be well thought-out so that it won’t interfere with any moving components in the differential. Also, at the very bottom of the cover you can see that the magnetic drain plug is also in place.
A bead of silicone is used to seal the new cover to the diff. Make sure you use an oil resistant RTV silicone. (RTV simply means it cures at room temperature.) I’ve always used Permatex “Ultra Black” silicone for this purpose because it is high-temp and resistant to oils, but this time I’m trying Permatex’s Gear Oil RTV Sealant.
Now the new cover can be bolted up using the included stainless steel Allen bolts.
In most cars you have to pump the gear oil into the housing, but there was so much room underneath the Jeep that I was actually able to pour in the Lucas Oil 80W-90 gear oil right into the housing using a funnel for zero mess. It was glorious.
The dipstick features a CNC cut knurled knob that requires no tools to remove and should be easy to check even on the trail. There is also a beefy O-ring to eliminate leaks.
Here’s a look at our finished work with the B&M diff cover installed on the Dana 44 housing in the rear.
It is tougher to see because of the steering components, but here’s how the cover looks on the Dana 30 diff up front. Total time for this project was just a bit over an hour, including clean-up.
