What would you say if we told you that you could get a vacuum-actuated selectable locker for just about any axle in any truck? What if we told you that this locker was CNC-machined and heat treated to be stronger than anything else on the market, that it came with a five-year warranty, and prices started at $689? This dream locker wouldn't require electric wires, cables, or a high-pressure air pump, and it could be engaged in an emergency with a spare bolt should the vacuum system ever take a dump. We know what you'd say: "Where can I get it, and why haven't I seen it before?" The answer is simple: It's made in Germany by a company called Offrotec, and now you can get it here in the USA.
When we met Daniel Tibus, of Tibus Off Road, he was driving his Unimog-axled GMC 1/2-ton we showed you in "Desert Dogs" (Aug. '02). Since then he has really taken an interest in the American off-road market, so much so that he is planning to move to southern California to better supply it. So while other 4x4 magazines were slobbering over new shifter knobs and spare-tire carriers in Moab we were on the trail learning about some of the European off-road products that we just don't see here in the states. It turned out that Tibus was working with a few partners to construct a selectable locker for any application you could ask for. Fast-forward to today and we can't believe how many differentials he offers! You'll just have to check out his Web site, www.killeraxles.com, to see for yourself. Soon his application list will include 101/2-inch 14-bolts and even 21/2-ton Rockwells! And the German innovation doesn't stop there. Currently the Offrotec locker is vacuum actuated, but future versions will use an electric solenoid. So take a look at the first U.S. photos of this new Offrotec locker and watch killeraxles.com for the latest news on U.S. distribution. And remember you saw it here first!
 02. Behold the newest selectable...  02. Behold the newest selectable locker available on U.S. soil. No, it's not an Eaton or new ARB. This heat-treated billet steel baby comes from Offrotec in Germany, where it has been used and abused in European truck rallies. Since we know many of you are dying for new options in the selectable locker market, we had this 35-spline vacuum-actuated Dana 60 version airmailed to us so we could test it and tell you whether to add it to your Christmas list this year. |  03. To find out what makes...  03. To find out what makes the new Offrotec differential tick...er...lock, we snuck ours into the back room of Off Road Unlimited in Burbank, California, for a top-secret locker autopsy. When the technicians at ORU disassembled the Offrotec locker we were impressed by the precision machining and how much beefier this differential is than any other Dana 60 unit we've ever seen. The guys at ORU figured out that this differential locks by sliding eight steel pins (A) in and out of receiving holes (B) on one of the differential side gears. This design means that you'd have to shear all eight pins or break all eight high-strength bolts (C) that hold the two differential halves together in order to break the locker. |  04. Anyone who can properly...  04. Anyone who can properly set up gears in a Dana axle will find there are no surprises with the Offrotec. Early versions of the locker may have interference problems in some housings if the grooved steel collar that moves the locking pins rubs on the bearing support (arrow). But any chance of you experiencing the same problem has been eliminated by a recent upgrade to that half of the locker. |
 05. The Offrotec locker uses...  05. The Offrotec locker uses a sliding shift fork that's mounted in a new cast-aluminum differential cover. This design is similar to an Ox locker, but unlike the cable-actuated Ox, the Offrotec locker uses a vacuum diaphragm to push and pull the fork to lock and unlock the differential. |  06. When installing the new...  06. When installing the new differential cover, be sure to index the shift fork (A) into the groove on the differential's locking collar (B). To avoid gear-lube leaks ORU cleaned up both surfaces with a Scotch-Brite pad and sealed up the housing with clear silicone before adding conventional gear lube. |  06. When installing the new...  06. When installing the new differential cover, be sure to index the shift fork (A) into the groove on the differential's locking collar (B). To avoid gear-lube leaks ORU cleaned up both surfaces with a Scotch-Brite pad and sealed up the housing with clear silicone before adding conventional gear lube. |
 08. It might not look like...  08. It might not look like it, but there is enough tie-rod-to-diff cover clearance on GM and Dodge Dana 60 front axles, even with the dual steering stabilizers that were on our test vehicle. Where you will run into problems is if you want to install the Offrotec locker on a Ford or '94-and-up Dodge Dana 60 front axle. On these applications you will need to plug and redrill the vacuum ports in a different location, as they will interfere with the leaf- or coil-spring perch on those axles. If you don't want to (or can't) use the Offrotec differential cover, there are parts available from Offrotec to make the locker work with any differential cover. | 
9a. |  09a & b. With a flick of this...  09a & b. With a flick of this military-spec switch, the Offrotec locker shifts from a daily-driver-friendly open differential to a traction-terror spool. Plumbing the system is easy as you only have to hook up three vacuum lines on the back side of the switch: one to lock the diff, one to unlock, and one from a source of vacuum. In our case we used engine vacuum, but diesels can use an auxiliary vacuum pump--something most of them have anyway. |
 10. Because the Offrotec locker...  10. Because the Offrotec locker operates silently, the kit includes a shift-fork position sensor and light to tell you when the locker is engaged. While testing at Pismo Beach this dash-mounted signal became known as the "red light of traction." During our two days of testing we engaged the locker under every condition we could think of--except at full throttle--with one tire spinning, that could probably break any locker or axleshaft. The locker always did as it was told and engaged every time in less than five seconds. |  11. The Offrotec locker uses...  11. The Offrotec locker uses engine vacuum to actuate the shift fork, so the kit includes this filter/trap to keep moisture from getting sucked into the engine should you tear one of the vacuum lines under water. |  12. So how did it hold up?...  12. So how did it hold up? Well, even with a fire-breathing 454, 4.56 gears, and 35-inch Mickey Thompson Baja Claws, we didn't really expect to blow up anything in the soft sands of Pismo. About the most strain we were able to put it under was backing out of the steep-walled sand bowls, and even then we think we'd annihilate the Dana 60 U-joints long before we had locker trouble. We were more interested in how well the Offrotec locker would engage and disengage on the fly and under load. We weren't disappointed and you won't be either! |