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Traction Satisfaction

Installing a Detroit Locker will get you a traction reaction second to none!

Shelley Bernd Feb 4, 2005

There are burnouts and great burnouts, but the greatest burnouts of all are identified by two identical streaks of smoking black rubber on the pavement. Steve Cook of Steve Cook Creations in Oklahoma City is building a twin-supercharged big-block Camaro, which will have the horsepower to produce burnout greatness if those ponies can just get to the ground. That's where a locking rearend fits into the picture because big horsepower is useless without good traction. The owners and builders decided on the Detroit Locker for a number of reasons; the Detroit Locker is specified in the NASCAR rule book for Nextel, Busch, Craftsman Truck series, and is well known for bulletproof reliability in all forms of motorsports. This 800hp monster will probably find its way down the drag strip a few times and rebuilding a rearend at the track is no fun.

When most motorheads think of a locking rearend, the first one that comes to mind is the Detroit Locker. And that is because the unit can take almost anything you can dish out while maximizing traction by delivering 100 percent of the torque and power to both drive wheels. The unit also has the ability to unlock for cornering (with minimum occasional 'unlocking noise') and does not require a special lubricant. If you're worried about maintenance, forget about it. The Detroit Locker doesn't use friction plates, springs, or cones. Its reliability is legendary and maintenance free. With 40-plus years of experience, Tractech, the maker of the Detroit Locker, knows how to build a stout unit and produce rearends for anything from race cars to fire trucks to combat-ready armored vehicles.

Most of us shy away from rearend work because it has mysteries that are best left to specialists. Read on and you will see Steve Cook and his buddies from Muscle Car Parts in El Reno, Oklahoma, demystify a Detroit Locker install into a 9-inch rearend.

The first step in this job is to remove the axles from the rearend housing to establish clearance for the newly assembled unit. After the housing is cleaned and ready, turn your attention to the assortment of parts necessary to do the job. In this install, the pumpkin has previously been stripped and made ready with new bearings, shims, gears and other required items. From then on the work consists of installing the pinion and ring gears, setting preloads, installing bearings, checking pinion gear backlash, checking gear tooth contact patterns and shimming until the proper pattern is achieved.

Finally, the assembled unit is popped back into the rearend housing, the axles are reinstalled and the rearend is filled with lubricant. All that is needed now is to shoehorn that big-block into the Camaro and those twin black streaks will appear upon command.


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The first step in this job is to remove the axles from rear housing.

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Install the pinion on the pinion support and set the preload at 25 inch-pounds.

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Here is the Detroit Locker.

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Here is the carrier.

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Check the side caps for alignment.

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Install new bearings in the carrier.

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Here is the new ring gear and the already installed pinion gear.

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A .030 shim is fitted to the pinion support. In this case it does the trick, but other shims may be needed in your install.

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Install the pinion support on the carrier and torque to 40 ft-lb.

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Fit the ring gear onto the locker.

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Turn the locker over and install the ring gear bolts. Use red LocTite and torque to 40 ft-lb in a crisscross pattern. Then, torque to 60 ft-lb.

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Place the locker into the carrier and oil all bearings with 80-90-weight gear lube.

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Install the locker into the carrier along with the preload adjusters and side caps.

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Use a dial indicator to check backlash. These gears called for .008 to .010.


Madison Heights, MI 48071
Oklahoma City, OK 73149

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