OPEN differential never puts more than 50% of the power to either axle shaft... Normally, 1) both wheelspropel the vehicle, 2) the differential's spider gears are stationary, and 3)the axle shafts spin at the same speed as the ring gear.
- When one wheel has no traction (torque load), the spider gears spin to balance the power between it and the wheel with a load.
- The spinning wheel has the same (balanced) force as the stationary wheel and spins at twice the speed of the ring gear.
LIMITED SLIP differentials can put up to about 70% on either (a single) shaft.
- By braking the wheel with no traction at the differential, the wheel with traction can get a higher percentage of the power applied.
- Each shaft spins but neither spins the same speed as the ring gear until both wheels have traction.
LOCKERS put 100% of the load to each axle.
- It's normally a shared load but when a wheel has no traction, the other still gets 100% of the power applied.
- The axle shafts always spin the same speed as the ring gear.
Open differentials are why people can get away with running bigger tires on smaller axles. The axle shafts don't get the same stress as a locked differential
Limited Slip = Posi Traction. Same exact thing. Posi Trac or Saf T Trac, or Traction Lock, or Trac Loc, or Sur Grip.......all just other names for limited-slip differentials. They pull both wheels, but allow slippage around corners.
Locker = Axles are locked together and there is no slippage at all when it is locked.
There are different ways of getting one locked.
Selectable lockers, like ARB, Ox, and E-Locker. Typically, these are open differentials when off, and totally locked when on.
Then you have ones like Detroit, Powertrax, etc.
These are locked when power is applied to the pinion, and unlock when power is taken away. So when you're on the gas, they lock, when you let off, they unlock so you can corner. They aren't unnoticeable like a limited-slip, and you will likely hear some popping/banging/jerking around corners....your mileage may vary here. I had an old Detroit years ago, and the first time I took a corner I though the back of my Jeep had fallen off. Got used to it, though.
There are others variations on this. Auburn makes a "locker" that is a limited slip when unlocked....and honestly, when it's locked it's not TRULY locked....it just tightens the hell out of the clutch pack so it's practically locked, but it CAN slip under the right conditions.
A Posi-traction unit (Chevy's terminology)
is a Limited Slip Differenial. LSD's have clutch discs in each side of the carrier that allow some slippage between each side. Lockers do not allow slippage at all when engaged. Slippage in a LSD will be smooth and not noticeable (unless its
really tight and you're making a tight turn). A locker unlocking with be felt and usually heard. They sometimes won't unlock when turning in a lighter vehicle and drag tires around corners like a spool or welded diff will also do.
The advantage is power being equally distributed to both wheels on the axle. That same trait is also a disadvantage on slippery surfaces like ice, as you'll just fishtail when in 2wd (sometimes even just drift sideways in 4wd). Its for that reason that selectable lockers have become popular. They function as either open diffs or LSDs when not engaged.
There’s something new to talk about around the water cooler or over a cold one around the campfire. After years of rumors, yarns, and gossip that it had gone the way of the Dodo and the Wooly Mammoth, the cable-actuated Ox Locker is back.
When Ox was first introduced years ago, it had only one competitor in the market: the venerable ARB air locker. Many flocked to what would be a more reliable cable-actuated locker-one that would not succumbto a faulty switch, a broken air compressor or a leaky air line. But locker engagement and disengagement problems kept the original Ox from achieving off-road manufacturing greatness, and the company faded away. Or so we thought…
We started hearing stories in 2005 that Ox Locker was making a comeback, and when those rumors became more persistent, we took it upon ourselves to learn more. Ox is now part of the Florida Manufacturing Group (FMG), located in Odessa, Florida, where the product line has gone through an extensive retooling and redesign. In its new, state-of-the-art facility, FMG manufactures the OX Locker and OX U-Joint products, as well as a big-rig product called Idle Buster and lift-access systems for the handicap.
During a recent tour of FMG’s facility, we were able to see firsthand that engineering and production are in fact moving forward with fervor and dedication. “[we are] 1000% committed to the OX product and all the products under the Florida Manufacturing Group,” Says Dan Youngman, President of operations at OX. “We have had some problems in the past, but what a lot of people didn’t realize is that the product issues that are out there, and on the Internet, are almost 3-4 years old.” We’ll vouch for this as we tested one of their new Ox Lockers in Moab, UT during the 2006 Easter Jeep Safari. (More on that later.)
The Facility Tour
We spent a day with the folks at FMG: looking at their manufacturing process, talking to employees, and ogling over their impressive CNC lathes, mills and other manufacturing machinery. There is a deep sense of pride in the facility, as every Ox product is made in house, using 100% American-made components. FMG refuses to skimp on the engineering, raw materials, or manufacturing. They are committed to making the best possible product-no exceptions. Their revised manufacturing process and new tools enable them to produce higher-quality products at three times the rate.
We watched as CNC lathes and milling machines shaped and formed huge blocks of steel and as forged diff covers were shaped to produce the lockers and u-joints. The impressive facility sports an enormous welding area, a complete powder coat facility, and an assembly
area called the “bat cave” where Chip, the resident tech guru, puts it all together. George Seiler, head of OX product management stated, “Let’s face it, you have to get the hardcore [rock crawler] guys to use our products to attract the non-hardcore guys too.” Their recent success with the pro rock crawlers have certainly proved just how strong their product is.
So what makes the new Ox product so special? After our military-level inspection, we realized a few things right off the bat. First, there is a commitment to excellence by every employee at FMG to build the best possible product. Second, every product is 100% American made. Third, the Ox product is the only one-and we checked-made from 8620 grade steel (ring and pinion gear grade steel). We also learned a few other things, such as Ox’s patented “back cut” tooth design, which provides for an easier and more completely locking of the mechanism. Further assessment showed that Ox uses a 4 pinion / 4 spider gear design on their lockers, whereas the competition uses a 2 pinion system to actuate, resulting in greater strength. Speaking of strength, the differential cover is absolutely massive. Our tour ended with the inspection of their newly designed locker actuating handle, which means the task of locking and unlocking the unit is no longer a chore.
Applications for Dana 30, Dana 35, Dana 44 (including super Dana models) Dana 60, AMC Model 20 are being pumped out, and you can expect the Ford 8.8 version soon as well.
Our installation began with assembling the locker. We started, as per the directions, by installing the 4 springs in the chamfered holes while Brian installed the thrust washer on the backside of the locking gear. We then bolted on the ring gear and proceeded to install the locking gear in the carrier assembly. Flat side up, we installed the patented OX, and locking ring gear. Next, we installed the carrier cap while paying special attention to make sure it sat flush with all of the 8 cams. Lastly, we installed the spring washers and ¼” bolts with lock tight, and torqued them to spec following the bolt map provided with the directions.
With the locker completely assembled, we prepped the rigs for installation. We removed the tires and brakes, then we drained the differential oil, removed the stock carrier and inspected the axle seals.
Next, we cleaned the empty differential housing and installed bearings and shims per spec. (You will need to resource an install kit for your gear set to perform this part of the install). After checking and rechecking the gear set-up, we reinstalled our bearing caps, torqued them to 45 lb-ft, and proceeded to reinstall the axle shafts and brakes.
Shifter Mechanism
In order to install the shifter cable, we began by installing the cable rod into the cover, followed by the cable (short fitting end). We then routed the cable to the cab, making sure to avoid any moving parts and hot zones (shocks, springs, control arms, exhaust, etc.) as well as avoiding any sharp bends or kinks in the cable. Be sure to install a grommet in the hole you make in the firewall to eliminate friction and to seal it from the elements.
We then sealed and installed the diff cover making sure the shift fork mated with the locking ring, and then torqued the bolts to 30 lb-ft, per the directions.
With the cable and differential cover installed, we set up the shift handle by threading the shifter piston into the rod end. We then installed the spring and swivel fitting into the shift rod. Some adjustment was necessary, but once complete, the shifter was ready for mounting. We then tied up the routed cable underneath the vehicle and partially tightened down the shift knob. We had to be sure the shift knob was not threaded all the way as to allow for clearance for the spring cap. Be sure to mount the shifter in an easily accessible position for ease of use and future adjustments if needed. We re-filled the gear oil to spec, completed the install,
