If you have been wheeling for a while, you may have heard that sharp snap when an axle breaks. It is not an affirming noise, and it can happen for a variety of reasons. One of them being oversized tires putting extra strain on stock-size driveline. For Jeep JL and JT owners, a FAD (Front Axle Disconnect) device is a known front axle weak-link. So if you are not ready for a $7,500 Dana 60 front axle replacement upgrade, a FAD delete is a viable solution.
Jeep implemented the FAD, also known as MAD (Manual Axle Disconnect) on some JL Wrangler and JT Gladiator vehicles equipped with either the Dana 30 or Dana 44 front axle assembly as a fuel mileage improvement device. It essentially frees up the front axle from rotating when four-wheel-drive is not engaged. The FAD’s sliding collar design becomes a “fuse” for the multi-piece front axle.
It also adds many more moving parts, electronics, and a host of potential other issues for enthusiasts who use their vehicles off-road. In technical off-road conditions with oversized off-road tires (37-inch diameter or greater), the FAD can potentially fail, leaving you stranded in the outback with only two-wheel drive. If you have lockers, you could still have “three”-wheel drive with one front wheel still pulling. Eliminating the FAD, the collar, and the OE front axles, and replacing them with a solid one-piece chromoly axle shaft greatly strengthens and upgrades a FAD-equipped axle assembly.
Jeep Rubicon FAD Delete With A Yukon One-Piece Chromoly Axle Kit
On a recent trip over the iconic Rubicon Trail, we discovered that our testbed 2019 Jeep Wrangler Rubicon two-door needed more ground clearance for future rock country trips. That is when I started contemplating upgrading to 37-inch tall tires. While enjoying the beauty of the Rubi, we talked with fellow travelers about their experiences and learned of their concerns over their damaged FAD units.
The OEM Dana 44 axle is very dependable with tires up to 35 inches in diameter but could be susceptible to breakage when 37-inch or larger tires are mounted on the Jeep (especially with the higher-traction tread designs).
Having to winch off a Rubicon rock proved that the Jeep needed taller tires and more ground clearance.
Upon returning home, we did three things: ordered new 37-inch tires and a Yukon FAD delete kit. We also lifted the Jeep about 2 inches. This was our magic formula and allowed us to still fit in the garage. We selected Yokohama Geolandar G003 M/T 37X12.50R17 tires because we’re very familiar with them. We have been using the 35-inch Geolandar M/Ts for more than five years.
Yokohama Geolander Tires
Yokohama tires have a definite aversion to spinning. They grip like you’re fingers to the steering wheel when you driving down a steep 20-foot ledge. These tires work so well off-road, that I very rarely use the Jeep Rubicon’s lockers—no matter how rough the terrain. This high rate of stickiness is both good and bad news: the good news is that you’ll rarely get stuck; the bad news is that it can break things (like axles).
Not even mounted yet, and the new Yokohama Geolandar G003 M/T 37X12.50R17 tires look very aggressive.
Yukon Gears FAD Delete Kit
Hence, the Yukon 4340 chromoly axle kit (P/N: YA W24172). This axle upgrade consists of four axle shafts and two U-joints. The only modification from stock is to remove the factory axle support bushing. The kit was released in October 2019. An official instruction sheet was never published as it became a part number to simply reinstall in place of the OEM shafts.
Yukon’s one-piece chromoly axle is on the bottom, while the OEM two-piece axle is on the top. The splined sliding collar is plainly visible. The shiny machined band next to the splines on the right side axle is where the central bearing supports the axle.
Yukon Chromoly Front Axle Kit FAD Delete Product Details
Yukon high-performance axles are built with high-tensile strength 4340 chromoly, using superior production methods that include cold-roll formed splines and feature advanced induction heat treating to create an axle of unmatched quality and durability.
- Fits Dana 44/M210 differential with FAD delete
- 32-spline
- Includes inner and 6.3-inch outer axles for both sides
- Includes 1350-/7166-Series u-joints and hardware
- Heavy-duty 4340 chromoly axles
The job starts with removing the front tires and front axle. The FAD control unit was unplugged and chucked into the trash bin.
We tapped our friend Nate Larocque to help complete our FAD delete operation. He started by placing the Jeep on a lift so that both front tires were off the ground. The brake caliper, rotor, axle nut, and hub were all removed. Next, the front axle was carefully disassembled and slid out from the axle housing. You can see that the U-joint is exposed to the weather and trail conditions.
Pro Tip: Plan It Out
When doing a job like a FAD delete, take advantage of the scenario and consider other upgrades and maintenance such as gear changes, an Eaton eLocker, brake upgrades, or whatever else will take your rig to the next level.
Nate is carefully inserting the new Yukon chromoly axle into the Dana 44. The new one-piece axle is in place, so the hub, axle nut, rotor, and caliper can now be reinstalled.
In our case, the Jeep was already set up to our liking, so it was a simple procedure to remove the front axle and replace it with our upgraded Yukon heavy-duty 4340 chromoly axles. With the new one-piece axle replacement loaded into the Dana 44 housing, the hub, axle nut, rotor, and caliper were reinstalled.
In a light-hearted moment, we used one of Nate’s sons to torque the lug nuts. His weight of 55 pounds on a two-foot breaker bar equals 110 pound-feet of torque.
The local Discount Tire dealership did an excellent job with the huge off-road tires (they’re dead steady up to 75mph) and you can buy a dynamite warranty that will replace the tire even if you slice it open on a rock.
Modifying Modern Vehicles Requires Modern Solutions
When modifying a Jeep JL or JT such as adding larger tires, gear change, and even the FAD delete, it is going to cause havoc. In each case, the Jeep ECU must be re-programmed to inform the vehicle of new or different equipment. These operations will not expressly void your vehicle’s warranty, but check with your dealership just for your peace of mind. Also, keep a documented paper trail on what they say since Jeep and Stellantis are a bit notorious for voiding warrants on highly modified vehicles.
In the case of the FAD delete, once the FAD is disconnected it can no longer communicate with the transfer case. Use of four-wheel-drive modes and off-road system functions like engaging the lockers and sway bar disconnect become inoperable. Since the FAD computer is married to the Jeep transfer case, a solution needs to be implemented.
In other scenarios such as when larger than the OEM diameter-sized tires or a differential gear change has been installed, the Engine Control Unit (ECU) needs to be reprogrammed for two reasons: speedometer accuracy and maintaining proper transmission shift points.
Programmers And Calibration Tools
Superchips is a well-known and reputable company that has many specialized Jeep products that can handle these tasks and more. The TrailDash 3 is the most intuitive device and may require a PCM swap to unlock all capabilities and functions. Superchips has optimized the PCM swap program with a streamlined shipping process that is included in the purchase price.
For those wanting to avoid the PCM swap, Superchips offers the Pulsar. This is a shift-on-the-fly performance programmer and calibration tool that connects directly to the vehicle’s computer with no additional wiring harness required. No PCM swap is required! There are other options out there as well such as the popular Tazer device from ZAuto.
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Back on the rocks but now without a care in the world about the 37-inch Yokohama tires gripping too well.
