As many readers already know, classic Jeep Cherokee XJs are some of the most capable new 4x4s available today. In addition to winning our 1997 Four Wheeler Of The Year competition, a Cherokee can be modified to excel on both the street and in light trailwork, as we've shown with our Project "Road and Trail.''
This time, we'll address the hardcore trail contingent. Equipped with solid axles front and rear, Cherokees already have half the battle licked. However, when locking differentials and larger tires become part of the mix, a swap to some stronger axles makes sense. ARB locking differentials, 4.56:1 gears, and 33-inch tires are a part of our plan. And when you combine these hardcore parts with the stock Dana 35C rearend, you get hardcore snappage. The Dana 35 uses C-clips to retain the axle shafts, and under extreme use, these can break and slide the axles out of the tubes. Thirty-fives also use 27-spline axleshafts, which are not designed for the stresses of locking differentials and big tires. A custom Dana 44 rear axle is a good swap candidate because it not only has an 8.5-inch ring gear and beefy 30-spline axle shafts, but it can also be equipped with disc brakes for increased stopping power.
While the frontend is the smaller Dana 30, it really is quite a decent axle. It has the same U-joints (Spicer 5-297X) as the larger Dana 44. The weakness of the Dana 30 is in the super-small 7-inch ring gear, the 27-spline axles, and the lighter axlehousing. Our Project "Teal J'' runs a locked Dana 30 with 4.10:1 gears and 33x14.50 tires, and has lived so far under some fairly extreme trails. However, since we'll be running 4.56:1 gears on this vehicle, and since we . . . um . . . happened to snap our Cherokee's Dana 30 housing in half on a 'wheeling trip (don't ask), we decided a matching front Dana 44 with beefier axle tubes and inner axleshafts would fit the bill.
We decided to have Currie Enterprises, renown for their stout Ford 9-inch and new high-pinion 8.8-inch axles, build us some custom Dana 44s. Currie uses a special forged alloy steel to build its axleshafts. These have a deeper case hardness than stock shafts, and when compared to the stock 27-spline rearend, offers an easy 40 percent increase in strength. Currie is expanding its line of stout custom axles and now offers custom Dana 44s and Dana 60s. It has also expanded its manufacturing facility and can now perform installations.
To save costs we elected to stay with the stock 5-on-41/2 bolt pattern. This allows us to retain our stock front brakes and unit-bearing inner axles as well as upgrade the rear 44 to disc brakes from the Grand Cherokee. Though the unit-bearing hub is a full-time setup, we've had good luck with them in the past. For those wanting manual hubs, Warn's Manual Hub kit is easy to install and is available for any full-time Dana 30.
When building custom axles for any vehicle, altering width from stock is easily feasible. However, we consulted the Off-Road General Store, as it will be building a custom suspension for our Cherokee. It determined our Cherokee's stock axle width--combined with their suspension and the proper offset wheels--will allow 33-inch tires to fit at full articulation, albeit with slight fender trimming. We've driven the store's Cherokee with these same modifications, and it seems to be the perfect setup for hardcore trail use and comfortable streetability.
In the next installment, we'll address the custom suspension for the Cherokee and the installation of our Currie Dana 44s. We'll also solve the rear driveshaft angularity problems with a tailshaft conversion kit for our NVG 231. Once it's all dialed in, we'll head out to the trail to give the new setup a thorough workout.
We opted for ARB Air Lockers front and rear. ARBs offer the best of both worlds for a street-driven rig because at the push of a button, both diffs can go from open to locked, providing true four-wheel drive.
The 4.56:1 gears from Precision Gear will provide our Cherokee with a crawl ratio of 34.7:1. However, since we have the four-speed automatic, the torque multiplication from the converter will make that number closer to 70:1.
Here's a comparison of our stock Dana 35 rear axleshaft with the new Currie 30-spline units. The increased diameter, along with the alloy forging and deeper case hardening, make the Currie shafts about 40-percent stronger than stock.
Our bare Dana 44 rear housing measures 551/4 inches flange to flange, within 1/4 inch of our stock housing. Off Road General Store will weld on the spring pads and shock mounts at a later date for correct driveline angle and suspension geometry.
Ring-and-pinion strength is another benefit of stronger axle assemblies. As gear ratios increase numerically, ring-and-pinion strength decreases unless you swap to stronger axles along with the gear change. Notice how much stronger our Precision Dana 44's 4.56:1s look compared to the 3.55:1s from the Dana 30.
Currie uses a spreader to accurately set up our new rearend. With the housing spread .0007 inch on each side, we can install our new carrier.
Backlash is then set to .0008 inch. Backlash is critical because it will determine whether the gears will be quiet and long-lasting or noisy and prone to failure.
The ring-and-pinion now mesh perfectly. For the ideal pattern, these marks should be in the middle of the ring gear. When installing Air Lockers, be sure to route the air line properly and test the unit before final assembly.
With the bearings pressed to the axleshafts, we can now install them along with our new Grand Cherokee rear disc assemblies.
The new disc brakes measure 113/16 inch. And with the right proportioning, they will compensate properly for our larger wheels and tires.
We decided on this stout diff cover from LPW because it provides carrier cap stabilizers for our abusive application.
Our front Dana 44 also measures the stock width. All the bracketry is stock Cherokee, but modified as per Off Road General Store specs for proper caster and driveline angles.
These lower knuckle supports are trademarks of any Currie front axle. The additional gusset/skidplates for the lower control arms are a must for heavy-duty four wheeling.