Made-to-Order
Swapping a Stock Dana 35 for a Currie 9-inchAny Jeep owner who engages in serious off-roading will likely snap a rear end; it's just an accepted risk in pursuit of the adventure. Swapping to a stronger rear end comes at one of two times in a vehicle's lifetime: when there's breakage or when the owner has the foresight to prevent breakage.
Currie Enterprises has a solution for both. A Currie-Built Rearend (CBR) is a premium kit that includes a bolt-in axle housing with vehicle-specific heavy-duty suspension brackets, a properly prepared third-member with the desired gear ratio, high-strength axles, choice of drum- or disc-brake assemblies and all necessary hardware. Based on the Ford 9-inch design, a CBR is built with all-new components designed for strength. None of the parts are rebuilt or reconditioned used pieces from a salvage yard.
The Currie-Built Rearend (CBR) system can be ordered with a variety of options and is shipped ready for assembly and installation. Basic handtools, RTV silicone and spray lubricant are needed along with a floor jack and jackstands. An impact wrench will help but is not necessary. A buddy will be helpful for a few steps.
The rear of the vehicle is raised and safely supported on jackstands and the rear wheels removed. The driveshaft is disconnected and removed. Be sure to watch for fluid coming out of the transmission. The adapter U-joints can be installed now or before the driveshaft is re-installed.
The Currie rearend can be fitted with drum or disc brakes. If the customer selects drum, the E-brake cable must be disconnected at the brake and secured out of the way.
If disc brakes are selected, new E-brake cables are available through Currie. The stock cables can be disconnected at the equalizer yoke and upper links and then removed with the stock axle. The main brake-line feed and axle-vent tube are also disconnected at the junction block on the axle.
A CBR might seem like an expensive solution for a busted ring or spider gear in a stock unit. Those problems can be repaired at a reasonable cost. But can you afford to make the same repair again if you keep going off-road or if you want to attempt tougher trails? Also, just about any one with entry-level mechanical skills and basic hand tools can perform this swap. A broken rear differential should be repaired by a trained technician, so labor costs enter into the bottom line.
When swapping to a stronger rear end, most Jeep owners won't stop there. Stronger links, taller springs, appropriate shock absorbers and beefier brakes are usually considered. With so many choices, Currie builds the rear end to suit those needs. If a different pinion angle is required, then the welding jig is adjusted. Lower gears are needed to support larger tires, just let Currie know the ratio needed; or tell Currie the tire size and tech support will recommend a ratio.
With the floor jack supporting the axle, the nuts on the upper and lower links can be removed (but don't remove the bolts, yet) and the lower shock-absorber bolts can be removed. The swaybar brackets are also removed; the swaybar can hang out of the way from its links. The axle is lowered with the floorjack just enough to remove the coil springs, then the upper-link bolts can be removed at the axle.
The rear end must be lowered to access the Panhard bolt in front of the fuel tank.
The lower-link bolts are removed and the links disconnected at the axle, allowing the rear end to be lowered and pulled out from under the vehicle. Be sure to save all the hardware.
The Currie axle housing is cleaned, and the third-member-gasket dressed with a bead of silicone on both sides.
The beauty of this system is how easily it can be upgraded, especially when dealing with brakes. Currie worked with three major brake suppliers to standardize many of the dimensions. Choice of axles or wheel-bolt pattern size won't interfere with installing either Currie drum brakes, Currie Explorer disc brakes or disc brakes from Baer, Stainless Steel or Wilwood. With a removable third-member, gear ratios and locking devices can be swapped with ease.
To illustrate just how easy the CBR system is assembled and installed, we followed the procedure on a stock TJ. The swap took less than five hours with an experienced mechanic, Tony Sato, handling the tools. But owners with average wrench skills and a friend or two can easily finish the job in a day in a driveway. Access to power tools and a lift will reduce the time even more.
Preload, backlash, pinion depth and other adjustments are already made when the third-member is shipped from Currie, which is positioned on the housing.
All the nyloc nuts are first snugged to seat the third member, then tightened to 40 ft-lbs in a criss-cross pattern.
The right and left disc-brake backing plates are positioned on the axle using T-bolts. The axle seal is coated with silicone and the axle splines are dressed with anti-sieze before each axle is slid into position. Remember, the long axle goes on the passenger's side and the short axle goes on the driver's side.
The stover nuts that secure the axle retaining plates are tightened to 40 ft-lbs.
Necessary tools include basic wrenches and sockets in both standard and metric. Also, hammers, pry bars, a floor jack, jack stands and a torque wrench will be needed. An impact wrench speeds up disassembly but isn't necessary. Other necessities include RTV silicone, anti-seize lube and spray lubricant like WD40. Small boxes or trays to keep track of hardware will come in handy as will shop rags and a drain pan to collect any leaking tranny or brake fluid.
The vehicle should be parked on a level surface with a chock or block placed under the front wheels. Once the vehicle is lifted and supported with jack stands, the rearend is supported with a floor jack. Removing the stock rearend is a routine operation. Currie suggests unbolting the shocks at the lower mount, then loosening and removing the nuts — but not the bolts — on the upper and lower links. Once all the brake lines are disconnected, the link bolts can be removed and rearend lowered to remove the coil springs. Once the Panhard bar is disconnected, the rearend can be removed from the vehicle.
The rotors are positioned and the calipers bolted in place. The brake-line flex-hoses are also installed. Note the bulkhead fitting for the hose. These come separate and must be welded on or secured with a hose clamp.
Here is a comparison view of the finished Currie assembly next to the stock Dana 35.
Before the Currie axle is installed, the case is filled with three quarts of gear oil. New brake lines can also be fitted between the flex hose connections and the junction block.
When inspecting the CBR parts, customers will notice a few unique features about the kit. All the joints on the axle housing are MIG welded and the housing ends have the larger Torino-style bolt pattern. All the brackets are laser cut and MIG welded to the housing. On the TJ, the Panhard or trac-bar mount has multiple holes to accommodate different lift kits. The shock mounts are rolled back enough to allow more clearance between the shock absorber and spring pad. Also, the spring indexing hub is already drilled and threaded for aftermarket bump stops. Finally, the 31-spline, 1541 forged axles are double drilled for both 5-on-4.5 and 5 on 5.5 bolt circles. The third-member assembly featured a Detroit Locker with 4.57:1 gears.
For this install, the Currie 11-inch disc brake kit based on the Ford Explorer design was used. Currie also offers 11x2.25 drum brakes and a choice of popular high-performance aftermarket disc-brake kits with up to 14-inch diameter rotors and 4-piston calipers.
The rear end is positioned under the vehicle.
With the spring positioned over its perch, one side of the axle is lifted so that the links and shock absorber can be reconnected. If stock links are used, the ends may need grinding to fit in the Currie bracket; aftermarket links will not have this problem. The other spring is then installed in a similar fashion.
The new e-brake cables are bolted to the upper links and the sway-bar is bolted in place. The main brake-line feed and vent hose are installed.
With a new adapter U-joint, the driveshaft is installed. Final chores include bleeding the brakes and lugging on the wheels before giving the vehicle a test drive.
Hard brake lines must be installed, but there are no provisions to mount the lines on the rearend. Currie can supply steel lines with all the necessary fittings.Currie also has flex-hose kits to the calipers than include weld-on bulkhead fittings. These fittings were already in place on the axle we installed, but the fittings can either be tack-welded or secured with a hose clamp. We did bend new hard lines from the bulkhead fittings to the stock junction block, which was adapted to the Currie rearend at the vent-tube provision by drilling and tapping the hole. A customer can also mount the stock junction block with a hose clamp. If drum brakes are used, then the stock E-brake cables can be retained. When switching to disc brakes, the cable must be changed. Currie can supply all the necessary parts.
Assembly of the rearend is straightforward. A silicone seal helps secure the third-member to the axle housing. The axles come in two different lengths: the longer one is for the passenger side and the shorter one goes on the driver's side. Once the Currie rearend is installed, the brake lines must be connected and the brakes bled. Currie recommends a 10-minute test run at idle while the rear wheels are lifted and the transmission is in gear. Allow the rearend to completely cool before taking the first test drive. For the first 100 miles, Currie suggests short drives of no more than 10 miles to keep the pinion bearings from building too much heat.