Tech article by Clay McGuill (eBronc)

You want traction? Get locked. Both wheels locked together on the same axle, all four wheels locked to the transfer case = maximum traction. No wheel slip, no spin. Just relentless, crawl-over-boulders-the-size-of-Volkswagens-even-when-one-or-two-tires-are-dangling-two-feet-in-the-air traction. "How", you ask?

Well, take your pick - you can weld the side gears to the carrier to prevent any axle rotation independent of the entire carrier itself (simple, cheap, and easy..but kinda permanent), bolt in a "lunchbox" locker that simply replaces the side and spider gears in your open or limited-slip carrier (in my experience, "limited-slip" diffs are usually more "slip" than "limited"), you can replace the carrier itself with a "sometimes" locker that is locked most of the time, but allows a little bit of wheel speed differentiation when cornering by ratcheting (and clunking, and banging, and popping that makes it sound like you've got a ring gear tooth or two broken off and flying around in the axle housing)...or, you can step up the user-selectable lockers-either air, cable, or electrically actuated.

Which one is right for you? It depends on lots of things-your vehicle, your driving style, the terrain you drive on, your budget, and how much you like lying in the mud underneath your truck at night on the trail replacing U-joints or axleshafts-or waiting for somebody to show up with a winch to drag you off the obstacle you're stuck on.

If your rig is a daily driver, your significant other drives it now and then, or you just like having complete manual control over your drivetrain, selectable lockers are a great way to go. They aren't cheap, but they are the ultimate in control. Turned "off", or unlocked, the axles behave just like open diffs-all four wheels are entirely independent of each other, making parking, sharp corners, and towing a breeze. Turned "on", or locked, all four wheels turn at the same speed, all the time, no matter what-at the flip of a switch of pull of a lever.

OX Lockers are mechanical lockers that replace the entire carrier in the axlehousings and use a cable-actuated shifter fork located in the cover to slide a locking ring sideways, engaging both axles and connecting them solidly together. The entire construction of the system is aerospace-grade quality - billet steel covers that are stronger than most skidplates, teflon-lined stainless steel cables, and massive, precise, beautifully machined carriers that are industrial works of art.

In this write-up, I'll document the installation of OX Lockers and 4:56 gears into both a Dana 30 and a Dana 44 axle. They're very similiar-the main difference being this particular Dana 30 front axle used a crush sleeve to set pinion bearing preload (the amount of torque required to turn the pinion shaft with the pinion nut tourqed to spec), while the Dana 44 used shims behind the inner bearing race in the housing to achieve the same result.

Let me take a moment here and give you something to think about. This is NOT an easy, bolt-on-in -a-couple-hours little upgrade..UH-UH. It's a major undertaking, and it involves some pretty specialized tools, a lot of patience, and a LOT of time. I'm not trying to talk you out of doing it yourself, but it took my brother and I 4 DAYS to get everything taken care of-and while we're not professional mechanics, we both have many, many years of experience working on all types of vehicles- from air-cooled VW's and Porsches to front drive imports, to '60's, '70's, and '80's Detroit iron-not to mention a pretty well-equipped garage (even better eqippped, now). Granted, we wasted quite a bit of time running around town to parts places, machine shops (that were closed), and tool supply houses (I LOVE HARBOR FREIGHT!), and some more trying remove the old bearings without the proper tool (hydraulic press) - but, still..even if everything had gone perfectly it would have taken at least the better part of two days. Think hard about doing it yourself, or paying a Pro to do it..and choose wisely.

Here's a list of the special tools you're going to need in order to accomplish the install-along with the usual hand tools, floor jacks, jack stands, air compressor, impact wrench, etc:
  • A hydraulic press -or at least have easy access to one. If you don't, don't bother even starting -you aren't going to get very far. No, don't be thinking a big gear puller or a vise and a BFH is going to work- 'cause it ain't. Trust me.
  • Make sure you have a BFH anyway-you might need it. (If you don't know what it is, you don't work on trucks much.)
  • A bearing separator -the kind that wedges behind the bearing and allows you to apply force to the entire backside.
  • A breaker bar -to torque the pinion nut while setting the pinion bearing preload.
  • A die grinder - to open up the old bearing races so they can be used as setup bearings-or you can buy setup bearings and races when you purchase the lockers and gears. (Spend the money-you'll be glad you did. Really.)
  • A big (I mean BIG) prybar -(useful for removing the old carrier from the axlehousing, holding the driveshafts while you remove and torque the yoke nuts, and getting stuck under the creeper wheels constantly while you're rolling around under your truck.)
  • A dial indicator with a magnetic base -to measure the backlash of the gearsets.
  • A precision caliper -to measure the bearing shims.
  • A 250 ft-lb torque wrench.
  • An inch-pound torque wrench -to measure the pinion preload.
  • A couple spray cans of brake cleaner -to clean the axle housings (and brakes).
  • 3 or 4 quarts of quality gear oil, a tube of Locktite, and some gear marking compound.
  • Lots of rags, paper shop towels, and hand cleaner.
  • A 3-day weekend -(if you think you're going get all this done in just a few hours, you're either an optimist, an idiot, or a mechanic on Walker Evan's race truck.)
Take my advice here and plan for your rig to be out of service for at LEAST a few days and have other transportation arrangements set up. You're probably going to need to run to the parts and/or hardware store at least once during the course of this project, and not having to rush things back together so you can get to work the next day really cuts down on the stress level, and keeps you from making mistakes and bad decisions at 2:30 in the morning. I know.

OK, you ready? Got everything lined up? Kiss the kids and wife goodbye for a while, take a deep breath, and jump right in. Park the truck on a clean, level surface. A garage floor is excellent-a sloping dirt driveway is bad. Of course, if you've got a hydraulic vehicle lift and a fully-equipped shop, that would be OK, too.
  • Jack it up and place stout jackstands under the frame where they won't be in your way as you're crawling around underneath the truck for the next few days. (They will, of course-but you can try.)
  • Remove wheels and tires and move them out of the way so you won't be stumbling over them all the time.
  • Place a drain pan under the diff housing and remove the cover-give the lube a while to drain, it's pretty thick. Inspect it for contamination-if it's foamy, milky, or has grit and dirt in it, it'd be a good idea to replace the axle tube seals during the course of the project. (See? I told you you'd be going to the parts store.) Also, think about lengthening the axle vent hoses.
  • On a Dana front axle, remove the hub/rotor assemblies (or drums and backing plates, if so equipped) from the outer knuckles so you can pull the axleshafts out of the housing. On a Dana rear, remove the drum (these can be stubborn), and using the hole in the axle flange for access, unbolt the 4 nuts retaining the axle to the housing. If you're lucky, it'll slide right out after a good tug-if not, either bolt the wheel back on the axle and use it for leverage, or use a slide hammer to persuade the axle out of the housing.
  • Check the carrier caps for markings so you can bolt them back the same way you take them out-if not marked already, use a punch to mark them clearly.

  • Unbolt the caps, and using a large prybar and most of your impolite vocabulary, "gently" remove the carrier from the housing-watch it, it's heavy. Don't give yourself a hernia. Also, don't drop the carrier on your toe.

  • Unbolt the driveshaft from the pinion yoke and secure it up out of the way with a coat hanger or something. Now, grab a long piece of angle iron and drill two holes near one end that match two of the yoke bolt holes. Use two of the u-bolt strap bolts to secure the angle iron to the yoke and still leave room to get at the pinion nut-this will hold the yoke while you zap the nut off with an impact wrench. Alternatively, you can use a LARGE wrench to try hold the yoke-but it's not easy.
  • Tap the pinion shaft out of the housing, making sure to keep track of bearings, shims, seals, slingers, crush sleeves, etc so you can put it back together in the same order. If this is your first time in a differential, I can't stress this enough!!
  • Remove the old bearing races from the housings.
  • Clean the housing thoroughly.
Now, you're about halfway there. Stop and take five. Have a beer. Eat something. Feel better? OK, back to work.

If you bought "cheater" or "setup" bearings when you bought your new gears, good for you-you can skip this step. If not, read on. Use the bearing separator and press to remove the old bearings from the carrier and pinon shaft (those bearings are ON there-after breaking a 5-ton 3-jaw gear puller AND an A/C clutch puller, we gave in and bought a hydraulic press from Harbor Freight-good thing they were open on Sunday morning) . Carefully record the shim pack thickness for each bearing, and DON'T MIX THEM UP. Use a die grinder to remove just enough from the inner diameter of the bearings so they'll just slip over the journals of the Locker carrier and new pinion shaft -and from the OUTER diameter of the old bearing races so they'll just slip into the housings. You'll appreciate this when you're constantly installing them and removing them as you adjust shim thickness to get the correct backlash and gear pattern setup. Clean the old bearings well after you're sure they're a slip fit.

I HIGHLY RECOMMEND READING THROUGH THE ENTIRE INSTRUCTION MANUAL FOR BOTH FRONT AND REAR LOCKER ASSEMBLIES!* Bolt the new ring gear to the Locker, making sure the mating surfaces are clean and free of burrs (always a good idea, in my opinion.) Depending on the gear ratio you are using, you may have to slightly disassemble the locker to get the ring gear over the slider sleeve. Put some Locktite on the new bolts and torque them to the correct value-usually around 80 ft-lbs or so. To prevent the carrier from turning as you torque the bolts, carefull wedge a screwdriver into the locking ring and engage the Locker-then grab one of the axleshafts and insert it into the splines of the locker carrier. Use a prybar on the wheel studs or just place a wheel over the studs and use the leverage to counteract the torque.

* This is a good time to grind off the edge off the corners of the pinion gears closest to the carrier. The instructions that come with the lockers tell you exactly where to grind. Put the pinion into your vise (use rubber or polyurethane jaw inserts) and use your die grinder to clearance the gears.

* Now, here's where you want to be really careful and take your time so you don't get things mixed up and yourself confused. You want to "trial-assemble" the gear set and carrier into the housing using the old (or "setup") bearings, shims, and races -BUT- subtract about .003" (3 thousandths of an inch) from the shim stack on EACH side of the carrier so it will just be a snug fit into the housing -not a major press-fit like it was when you removed it- and will be once everything's buttoned up again. Leave the NEW bearings, races, shims, seals, and pinion nut in the box they came in until you're happy with the backlash setting and gear contact pattern, and ready to assemble everything for the final time. * First, put the "setup" pinion shaft bearing races into the housing, with the original shim stack (on the 44) and/or slinger(on the 30) between the pinion gear and the inside bearing (the one closest to the pinion gear itself.) Some Dana 30's use a "crush sleeve" to preload the pinion bearings and don't use shims behind the inner race -if yours had one when you took it apart, one goes back in. Use the old one for setup and only put the new one in when you're assembling it for the final time-once it's crushed, there's no re-using it. Truthfully, this is the point where you'll be glad you kept track of exactly how your diff came apart. The same models may have been put together differently in different years, and finding out exactly how yours goes back together will necessitate a call to an expert. Once the pinion shaft is in, slide the yoke over the splines and tighten the (old) pinion nut snugly. Carefully install the new carrier into the housing (with old shims and setup races). It should turn a little as the ring gear engages the pinion, and should need just a little persuasion to clunk into place. Tighten the caps just snug(make sure they're oriented correctly).

* Use a magnetic-base dial indicator (place the base on the housing flange and the pointer on the edge of one of the ring gear teeth) to check the backlash of the gearset-usually you want between .008"-.015". If it's too loose, the carrier needs to be moved sideways, closer to the centerline of the pinion shaft. If it's too tight, move the carrier away from the pinion shaft. To do this, you have to remove the carrier from the housing, remove shims from behind the bearings on one side and add them to the other (keeping the TOTAL carrier shim thickness the same- just moving the carrier sideways in tiny increments). Make small adjustments-like .003" or .005" at a time, and check the backlash every time. You'll see the backlash increase or decrease as you adjust shims-just keep adjusting until it's within range. Shoot for .010"-.012", if you can get it.

* Once you've got the backlash set where you want it, it's time to apply gear-marking compound to the ring gear teeth and turn the entire assembly an entire rotation, so the ring & pinion gears can mesh. You're looking for a contact pattern (the area where the marking compound is rubbed off) to be roughly oval in shape and centered on the gear teeth -top(crown) to bottom(root), and front(toe) to rear(heel). If the backlash is within range, the pattern SHOULD be OK top to bottom on the teeth, but if it's nearer the toe or heel of the ring gear than centered, you'll have to move the pinion shaft in or out to compensate. Moving the pinion gear towards the carrier centerline will move the contact pattern in from the heel of the ring gear in towards the toe, and vice versa. Keep in mind that moving the pinion gear in or out WILL affect the backlash setting (because they're hypoid gears)-so if you move it very far at all, it'll throw the backlash out of range and you'll have to move the carrier shims again to get it back. This can be a frustrating process-one change seems to have multiple effects, and you can end up chasing your tail. Just go slowly, think about what's happening, and you'll get it-it's not rocket science.

* Once you're SURE everything looks good, it's time to pull everything apart, clean the housing again, install everything with NEW bearings, races, crush sleeves, and seals (an old bearing race makes a great pinion seal installation tool). MAKE SURE YOU KEEP THE SHIMS TOGETHER AND KNOW WHICH ONES WENT ON WHICH SIDE. If you screw them up, you get to start all over. (This is not fun, by the way.) DON'T FORGET TO ADD .003" TO THE SHIMS BEHIND THE CARRIER BEARINGS ON BOTH SIDES BEFORE YOU PRESS THEM ONTO THE CARRIER. Use a brass punch to install the races into the housing so they aren't gouged, and don't forget the shims under the inner race, if applicable. Spread a little clean gear lube on the bearings and races before you install the bearings for the final time.

* First up is the pinion preload. For the 44, this is accomplished with shims between the pinion shaft and the outer bearing. Using the old pinion nut and washer (and whatever method you decided to use to keep the pinion from rotating) torque the nut to 100 ft/lbs and check your rotational resistance (preload). It should fall beween 20 and 40 inch pounds. Too much? Add shims, re-torque and check. Too little? Remove shims, re-torque and check. Once you have the preload correct, use your new pinion washer and nut and torque to 220 ft/lbs. On some D30's the preload is set using the crush sleeve between the two bearings will be crushed as you tighten the yoke nut. Because of this, you must apply torque to the nut carefully, checking the preload often. Preload should start occuring after you reach about 200 ft/lbs. Once your preload is between 20 and 40 inch pounds, you are finished with the pinion.

* Torque the pinion nut to 220 ft-lbs, then use the inch-pound torque wrench to rotate the pinion and measure the preload-it should be 20-40 inch-lbs for new bearings.The carrier should need a little "persuasion" to fit into the housing- a rubber or plastic dead-blow mallet (a BFH, in other words) works great. Torque the caps to 30 ft-lbs.

* Once everythings' back in and torqued down, check the backlash and contact pattern again-it may be a little different with the new bearings and races. If all looks well, you're done with the heavy work-now on to the Locker shifter and cable installation.

* Before you do anything else, decide where you want the Locker shifters to be. Sit in the driver's seat and try different locations around the interior until you find a good spot, and sure that the shifters won't interfere with the operation of anything else. Don't forget to allow room for the cables-they are rather large and stiff, and don't really bend around obstructions well.

* Once that's done, run the cables. This is harder than it sounds, because you've got to keep them away from the exhaust, driveshafts, transmission shifters, and moving suspension parts, while leaving enough slack to allow for suspension articulation. Try different routings until you've found one that allows the cables to reach the shifters without sharp bends, and is out of the way as much as possible. Tie wraps or small radiator hose clamps work well for securing the cables to control arms and frame brackets.

* Once you've got the cables run, install the cable end into the OX Locker diff cover. The easiest way to do this is to actually thread the cover onto the cable housing, instead of the other way around-the cable housing is REALLY stiff, and it only takes few turns to fully seat the threads on the end of the cable housing all the way into the cover. Make sure the threads on the end of the inner cable go all the way through the shifter fork "piston" in the cover, and leave 2 or 3 threads showing out the far side-if this needs adjusting, grip the shifter end of the inner cable with pliers and twist it until the cable placement is correct.

* Here's where you get to be patient-installing the shifters onto the cable end. Take the upper and lower pieces of the shifter apart, put the threaded "pill" into the lower pivot of the shifter assembly, and line it up with the end of the inner cable threaded end. Carefully twist the lower shifter assembly onto the inner cable end until a few threads show past the end of the pivot. Place the diff cover where you can see it and move the shifter at the same time. To adjust the cables so the shifter fork travel inside the cover corresponds to the shifter travel, adjust the brass barrel on the lower shifter assembly to thread the shifter either further onto or off of the outer cable housing. What you want is for the shifter fork in the housing to be all the way against the inner center wall of the cover when the shifter is the "Lock" postion. Keep adjusting the shifter until you're sure you've got full travel at the shifter fork in the cover-remember, the Lockers are actuated by PUSHING the cable-they're spring-loaded to return to "Open" postion when the shifter pulls the cable. When you're sure you've got it adjusted correctly, snug up the lock nut on the cable housing, insert the two screws that prevent the brass barrel from rotating, and tighten the nylon set screw for the inner cable end, then mount the assembled shifter in it's permanent home.

* Almost done now-just run a bead of silicone around the cover mounting flange and mount it to the axle housing (making sure the shifter fork engages the lock ring on the carrier), fill the diffs with lube, hook the driveshafts back up, re-insert the axleshafts into the housings, put the wheels back on, and clean up a little.

* To test the Lockers: With the wheels still off the ground and the shifters in the "Open" position, grab a wheel and turn it. The other wheel on the same axle should turn easily in the OTHER direction, indicating an OPEN diff. Now, click the shifter into the "Lock" position and try to turn a wheel-it should be difficult to turn, the other wheel should turn the SAME direction, and the driveshaft should turn, also..'cause now you're LOCKED UP! Ain't it cool?

* Some slight cable adjustment may be needed to insure the Lockers engage completely-just follow the directions and you'll get it. Take it easy on the new gears at first-drive 20 or 30 miles on the first trip, then let them cool down. Don't tow anything for about 500 miles or so, and change the lube to make sure any installation contaminants are flushed out.

Enjoy being locked up!