The New Gearless Locker
Gearless but not Gutless
by Randy Lyman

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For those of you who are interested in new mechanical designs, or more traction with fewer side effects, the Gearless Locker is more than just a little interesting. Trac-Tech started with the simple idea of the EZ Locker and has taken it even one step further towards simplification and smoother operation. Everyone from off-road fanatics to those who only need extra traction once in while will want to consider the new Gearless Locker.

The overall results of the Gearless Locker is that it's operation is the same as the Detroit Locker without the extra backlash. The unit drives both tires unless the vehicle is negotiating a turn, in which case it allows the outside wheel speed to override the inside wheel speed so that the tires do not have to scuff, or be dragged around the turn. The free-wheeling side re-engages and drives again as soon as the inside tire speed catches back up with the freewheeling side when the vehicle completes a turn, or the inside tire spins and reaches the same speed as the outside tire. The only side effects are strange handling in short wheel-base vehicles while negotiating sharp turns under power, and the spinning of the inside tire while taking off from a stop sign, while turning, when the road is slippery.

Finally, the long awaited and unexplained Gearless Locker is explained. The details may seem complicated at first, but read them a few times and give the information a few days to sink in before reading it again. Many readers will probably figure it out and say "why didn't I think of that?"

And the obvious question is "how does it do that?" The whole key to the operation of the Gearless Locker is the "Tunkenel-V" ramp. (is this a goofy name or what?) The force of the cross pin shaft on the Tunkenel V ramp produces a separating force between the cross pin shaft and the V ramp as the shaft attempts to ride up the ramp. This separating force on the V ramp causes a clamping force on the friction clutches, which locks the side gear to the case as the clutches engage and drives the axle, which drive the wheel. If any force causes the wheel to go faster than the ring gear that is driving it, the results of the overriding speed of the wheel will cause the force on the V ramp to decrease, and the clutches will disengage allowing the overriding wheel to free-wheel until the overriding force causing the wheel to turn faster than the ring gear is gone (when the vehicle completes the turn). This may seem complex, but read it through a few times and then give it a few days to sink in before reading it again.

The idea of clutches may bring up concerns of chatter or wear. Unlike clutches in most applications, these clutches lock instantaneously and do not slip at all (which makes the unit work without the extra backlash associated with other lockers). They also release instantly when any overriding forces are created while negotiating a turn. This instant release design does not allow for any chatter whatsoever. Additionally, Trac-Tech states that in all of their extensive testing they have had no indication of clutch wear, and in fact, they provide a bottle of special additive to keep the clutch surfaces from galling due to the excellent loading of the friction clutches.

Installation of the Gearless Locker is pretty easy and straight forward. Most backyard mechanic will be able to install the unit on a long afternoon or at worst, over the weekend. Some models require removing the ring gear from the carrier, but none of them require any shimming. Like the EZ Locker from Trac-Tech, and the Lock-right from Powertrax, the Gearless Locker simply replaces the standard spider gears in a non-locking differential and works with the stock carrier case and the stock c-clips.

The first units to be released will be for the AMC Model 20 & Model 35, Dana 30, Dana 44, Ford 9", Suzuki, and for several Toyota applications.

These will work well in both the front and the rear just like other lockers. I know that a lot of readers are reluctant to try a locker in the front. I have driven vehicles with front lockers and find them to be fairly well mannered. I believe that the few small changes in handling are worth the gain in traction, and using a locker will allow the unlocking of one hub for better steering during steep off-camber maneuvers.

Gear Talk is written by Randy Lyman, founder and President of Randy's Ring & Pinion.

Originally published in the July 1999 issues of 4WD & Sport Utility Magazine.

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