Apr 042014

In response to racer feedback and OS Giken’s own observations of tuning trends, OS Giken has proudly released the OS Super Lock LSD for the Ford 8.8” (FD881-HA) Independent Rear Suspension differential. OS Giken found that it was becoming common to use the Ford 8.8” IRS carrier for high powered builds for many import sport compacts, due to the 8.8” large sized ring gear, low costs/high availability, and wide selection of available gear ratios. The OS Giken Super Lock is available for both 31 and 28 tooth spline axles. Both designs feature 20 active clutch plates.


All of OS Giken’s Super Lock differentials feature forged cases that are chemically heat treated, providing the highest level of durability and strength possible. Additionally, all Super Lock LSDs are fully tunable for any specific application. Please feel free to inquire with details regarding your unique needs and the engineers of OS Giken will be happy to provide a recommending setting!

Contact UNITRAX for more information on the FD881-HA OS Giken Super Lock.

Mar 052014

The revolutionary and race-proven OS Giken Super Lock is now available for the Scion FR-S and Subaru BRZ!

2013 Scion FR-S2

The OS Super Lock LSD is the culmination of years of extensive research and development that led to a revolutionary LSD design with the capacity to house an unprecedented number of friction plates (up to 28 plates in total). Combined with OS Giken’s patented lock timing system, the Super Lock LSD is able to achieve complete lock in a progressive, smooth, and quiet manner, making it outstanding for both street and racing performance.

OS GIken TY421-HA

An OS Super Lock installation can be performed in less than one day. Call or Email UNITRAX for more information.

800.622.4327 | info@GoUNITRAX.com


Jan 062012

The engineers at OS Giken have been very hard at work to bring an outstanding limited-slip differential to market.

The patented design is a revolutionary breakthrough in clutch type limited slip differential design and allows the Super Lock to have up to twice the friction plates compared to conventional designs. OS Giken’s quality craftsmanship and original design enables 100% full locking as well as unparalleled durability.

Corvette C6 1

Some of the unique features of the Super Lock are:

  1. Billeted and Heat-treated case (not found on most competitors’ units)
  2. Forged internals, and RAW-forged gear teeth (strongest gears available anywhere)
  3. More disks+larger disks = more friction surface area to dissipate heat and allow true 100% locking capability. OS units typically house TWICE as many disks as competitors units (up to 28+ plates) 
  4. Ultra-precise disk machining, which means the unit is ready to perform immediately after installation… NO BREAK-IN PERIOD REQUIRED!
  5. Non-intrusive cone spring design prevents unnecessary wear and results in consistent and reliable performance over the long-term.
  6. 100% locking and unlocking capability: True 100% lock results in no moving components results in no heat generation. The main reason other limited-slips fail is because too much heat is generated, since true 100% lock cannot be achieved. OS has yet to see one of their Super-Lock LSD’s fail in the field!

Viper LSD 1

In a recent press release from the OS Giken team,it was stated that “since released to the public in 2000, there have been ZERO failures of a production unit, and ZERO rebuilds necessary at any level, from street use to professional racing.”

Corvette C4

UNITRAX has been trained on how to tune the Super Lock to meet specific requirements. The unit that we trained on, we thought, was a new unit. However, the tech from OS Giken informed us that the Super Lock was removed from a car that competed in three full race seasons!

Recent additions to the Super Lock line are the C4 through C6 Corvette, all model years of the Dodge Viper, Camaro SS, FJ Cruiser, Chrysler, Dodge and Mercedes M215 differentials, BMW, Alpha Romeo, Porsche, and Mini. There are several new applications to be announced soon.

The Super Lock also fits most popular Toyota, Lexus, Nissan, Honda and Mazda differentials.

UNITRAX is excited to be able to offer such a well designed and executed LSD to the drivetrain performance community.

                   Viper LSD 2

Visit the OS Giken site at www.osgiken.net for more information on the Super Lock and the other outstanding product offerings including Clutches, Close Gear Ratio kits, Tranmissions and Engine upgrades.

Jan 052012

The Dodge SRT 8 | Mercedes M215 Wavetrac® has proven to be one of the best posi’s ever manufactured. From drag racing to road racing, the Wavetrac has made every owner extremely happy. The M215 differential is found in the Charger, Magnum, Challenger and the 300c. Call UNITRAX at 800.622.4327 for details.

Autotech Driveline Wavetrac®: Designed from a clean sheet using state-of-the-art knowledge and engineering to be a better differential than any other. It uses a patent pending design to improve grip in low traction conditions.


Wavetrac®: Gives you quicker acceleration and faster cornering by driving both drive wheels instead of just one. And, it offers improved no-load performance when compared to other helical gear differentials on the market.

The Wavetrac® differs from other torque-biasing differntials. To best understand how the Wavetrac® is truly different from the other gear differentials on the market, you first have to understand the primary problem that the Wavetrac® solves.

The problem: Loss of drive during zero or near-zero axle-load conditions.

Zero axle-load is a condition that occurs during normal driving, but creates the most noticeable problems when driving in extreme conditions. Zero or near-zero axle-load is the condition that exists when there is ‘no-load’ applied through the drivetrain, when one drive wheel is nearly or completely lifted (often in aggressive cornering). It also occurs during the transition from engine driving a vehicle to engine braking and back, even with both drive wheels firmly on the ground.

Here’s how that loss of drive hurts you:

1) If you lift a wheel, all gear diffs except Wavetrac®, will NOT power the other wheel.

2) During the transition from accel to decel, all gear diffs except Wavetrac®, do nothing.


Why does this happen?

All gear LSDs (including Torsen®, Truetrac®, Quaife®, Peloquin, OBX, etc.) work in basically the same manner: they divide the drive torque between the two axles, applying drive to each side, up to the available grip of each tire. The amount of drive torque one wheel can get over the other is described as the bias ratio, a measure of the torque split across the axle.

Standard, open differentials have a bias ratio of 1:1. They can only apply as much drive torque as there is available traction at one wheel. When one wheel loses grip, the total available drive is lost as well (at a 1:1 ratio). All your power goes out the slipping wheel – along the path of least resistance.

Torque biasing differentials offer increased bias ratios over open differentials. For example, if a diff has a bias ratio of 2.5:1, then it can apply drive torque to the wheel with the most traction (gripping wheel) at 2.5 times the traction limit of the wheel with the least traction (slipping wheel). This is a significant improvement over an open diff… most of the time.

The problem is that when one tire has LITTLE or NO grip (zero axle-load), the other wheel gets ZERO DRIVE, because (basic math here): 2.5 x 0 = 0.

Lift a wheel (or substantially unload a wheel) and you get zero axle-load on that side – that means that during the time the wheel is unloaded, the typical diff will NOT power the wheel that’s still on the ground. No matter how high the bias ratio,you get no power to the ground.

During the transition from accel to decel, where you have near zero torque on the axle, even if the wheels are on the ground, the typical diff is unable to begin applying drive torque until AFTER the zero torque condition is over. While this condition is generally short-lived, the fact that most diffs can do nothing during that time means that there will be a delay once the zero torque condition stops – creating a reaction time in the driveline.

The Wavetrac®, however, is different:


The innovative, patent-pending, Wavetrac® device in the center of the diff responds during these exact conditions when zero or near-zero axle-load occurs. At or near zero axle-load, the axles (and therefore each side gear in the diff) start to turn at different speeds. This speed differential causes the Wavetrac® device to step into action:

Precisely engineered wave profiles are placed on one side gear and its mating preload hub. As the two side gears rotate relative to each other, each wave surface climbs the other, causing them to move apart.
Very quickly, this creates enough internal load within the Wavetrac® to
STOP the zero axle-load condition.

The zero axle-load condition is halted, and the drive torque is applied to the wheel on the ground (the gripping wheel)… keeping the power down.

Some gear differentials rely solely on preload springs to combat loss of drive. The drawback is that you can’t add enough preload to prevent loss of drive without creating tremendous handling and wear problems at the same time. So, to avoid these problems, the preload from ordinary spring packs must be reduced to a level that renders them ineffective at preventing loss of drive. The Wavetrac® is the only differential that can automatically add more load internally when it’s required.

In the case where both wheels are on the ground during zero axle load, such as during a transition to deceleration, the Wavetrac® device is able to prepare the drivetrain for when the zero torque condition stops, eliminating the delay seen with ordinary gear diffs.


What this means for you as a driver is that power is delivered to the gripping wheels for more time and in a more constant manner – making you faster and improving stability.

The Wavetrac® truly is different – and its innovative features can make a real difference in your car’s performance.

All Wavetrac® differentials include a transferable, Limited Lifetime Warranty.

Wavetrac® differentials are currently available for Ford, BMW, Volkswagen, Honda and Mitsubishi.

Call UNITRAX for more information at 800.622.4327.


Jan 052012

O.S. Giken is now shipping the OS Super Lock LSD (CH061-HA) for 2010 and 2011 218mm Camaro V8 differential. The Super Lock weighs in at 30 pounds.

The OS Super Lock’s race proven design provides extreme durability, legendary reliability, and outstanding performance while still offering a comfortable driving experience.

UNITRAX 800.622.4327

Dec 132011

UNITRAX worked with Richard Kratz of Mopar Max Magazine to upgrade the drivetrain of the “Maulin’ Magnum”.

Part one of the article is in the December 2011 issue of Mopar Max magazine. UNITRAX installed the OS Giken CR031-HA Super Lock into the Maulin’ Magnum M215 differential and a set of the Driveshaft Shop CH56 Axles.

The “Maulin’ Magnum” is driven by Alex “The Car Girl” Rogeo. Alex and her crew chief Richard Kratz, made some changes to the “Maulin’ Magnum” and Alex changed her launch technique. The results  generated the team’s first 11-second passes. At the recent street-legal drags at Auto Club Dragway in Fontana, California, the last three runs were 11.66, 11.65 and 11.66, with the best being 11.65 at 118 mph.

Here’s a link to one minute in-car video of her first ever run in the 11’s. It’s fun to watch her reaction.

Part two, covering the installation of the OS Giken Super Lock and the Driveshaft Shop axles, will be in the January, 2012 issue of Mopar Max Magazine.

Mar 202011

Richmond Gear gear sets designed specifically for the popular 5th Generation Camaro.

A 3.55 (49-0192-1) gear set is offered  for the the LS / LT V6 Camaro.

The Camaros with the V8 engines have three gear sets to choose from; a 3.73 (49-0187-1),  a 4.11 (89-0003-1), and a 4.33 (69-0493-1).

The 4.10 gear set has been discontinued and replaced by a 4.11 gear set made of a higher hardness 9310 material. It is designed to handle more horsepower and improved longevity.

Talk to UNITRAX about ratio changing your 5th Generation Camaro differential.

UNITRAX 800.622.4327

Feb 022011

Four Limited-Slip Differentials For The Viper SRT 10 Positraction For Street, Strip and Track

The ‘Gen III” Dodge Viper SRT 10 was introduced in 2003 with fresher look, more power, and a new version of the Dana’s resilient 44ICA differential, the M44-4. Along with a new housing, the M44-4 was fitted with Dana’s Hydra-Lok limited-slip differential.

Because the 2003 M44-4 housing was designed to accept the Dana Spicer Hydra-Lok, the Viper community was initially left with no positraction alternatives. However, today the SRT 10 owner has four limited-slip differentials to chose from. Two of the units are engineered to meet the most demanding performance applications and a third is found in the 2008 through 2010 “Gen IV”  Super 44-4ICA Viper SRT 10.

Dana Spicer Hydra-Lok

Dana’s Hydra-Lok was originally developed by ASHA Corporation in Santa Barbara, California. McLaren Performance acquired ASHA and sold the rights of ASHA’s Gerodisc technology to Dana’s Spicer light duty axle division. Dana completed development of the unit and trademarked the LSD as the Hydra-Lok. Production began in Syracuse Indiana and in 1999, Jeep debuted the Hydra-Lok in the Grand Cherokee.

Gerodisc technology is speed and torque sensitive, operates full-time, and offers proportional torque transfer with progressive action. It uses the differential oil to operate the Gerotor. TwinDiscs provide one coupling per wheel. The fluid is released at calibrated pressures to engage the clutch pack.

The Hydra-Lok transfers wheel torque as conditions demand, ensuring improved traction and handling. Unlike traditional disc-based LSD’s, the Hydra-Lok offers controlled torque transfer. It does not waste power on wheel spin, rather it transfers torque to the wheel with the most traction. The torque is independent of the slipping wheel condition. The Hydra-Lok is speed-sensing meaning that the torque transfer is independent of the slipping wheel’s traction. The amount of torque transferred to the wheel with traction is based on the speed of the spinning wheel. Resulting in nearly immediate transfer of torque from the wheels that slip to those that grip.

According to Dana Corporation, when a Hydra-Lok equipped Viper begins to negotiate a curve, the vehicle reacts as if it had an open differential to reduce the potential of over-steer. As the vehicle continues through the corner, it takes on the characteristics of a limited-slip differential, transferring torque to the wheel with traction. Coming out of the curve, however, the Hydra-Lok allows the Viper to deliver the maximum amount of torque to the ground for improved speed while exiting.

The 2003 version of the Hydra-Lok had an issue with cross pins failures. UNITRAX developed a replacement 300m cross pin to help prevent Hydra-Lok failures. In 2004, Dana upgraded the Hydra-Lok with a heat-treated cross pin. However, side gear and pinion gear failures have continued to plague Gen III SRT 10 owners.

Unfortunately, dependability and durability issues have spoiled the promise of the M44-4 Hydra-Lok. We will now examine the alternatives to the Hydra-Lok.

Quaife ATB Differential

R.T. Quaife Engineering Ltd was the first manufacturer to supply a replacement limited slip differenital for the stock SRT 10 Hydra-Lok. The Quaife ATB (Automatic Torque Biasing) Helical LSD differential was originally developed in the 1980s and is used throughout world. While more widely designed and developed for front-wheel drive vehicles, Quaife Engineereing states the traction benefits offered by the ATB Helical LSD differential can also be utilized in rear-wheel drive vehicles.

The Quaife is an automatic torque biasing helical-gear based differential. Unlike a conventional plate-style limited slip unit, the Quaife ATB relies on sets of floating helical gear pinions that run in pockets and mesh to provide the normal speed differential action. Should one of the driven wheels start to spin however, the helical gears start to generate a torque bias thanks to the axial and radial thrust of the helical gear pinions in their pockets.  The result is that there is a progressive transfer of torque away from the spinning wheel of the axle to the driven wheel, which is now capable of transmitting a greater proportion of torque to a constantly varying degree.. The transition of power is smooth and constant without ever completely removing power from the other wheel. The effect is progressive but at no stage does the Quaife ATB lock solid. By getting the power to the ground, the Quaife enables the Viper to accelerate quicker and corner faster.

In cornering, while accelerating out of a turn, the Quaife ATB biases greater power to the outside wheel, reducing inside-wheel spin. This allows you to begin accelerating earlier, exiting the corner at a higher speed. The Quaife ATB provides straight-line acceleration that is close to an an ideal 50/50 power split to both drive wheels when traction conditions are ideal. The Quaife ATB also controls loss of traction when the drive wheels are on slippery surfaces by providing the appropriate biased traction needed to overcome these adverse conditions.

The Quaife ATB powers both drive wheels under nearly all conditions. The differential senses which wheel has the better grip and automatically biases the power to that wheel. However, it must be noted that if one wheel is in the air or on a surface without traction, neither wheel will be driven during that moment in time.

To install a Quaife ATB into the SRT 10 Super 44-3ICA differential, the stock output shafts must be shortened and bore-drilled to accept the anchor bolts.

To maximize the performance of the Viper equipped with Quaife ATB differential, the suspension should be set up like an open differential; stiff springs and a soft sway bar.

The Quaife’s distinctive design offers controllable traction, improves handling and steering, and applies the power where it is needed most. The Quaife ATB is exceptionally strong and generally requires no maintenance.

All authorized Quaife ATB Helical SRT 10 differentials come with a limited  lifetime warranty.

GKN Visco-Lok

The 2008 through 2010  “Gen IV” Viper SRT 10 is equipped with the GKN Visco-Lok. The Visco-Lok has been in production since 1999 and is a standard feature in the BMW M3.

The Visco-Lok is a unique hermetically sealed speed-sensing limited-slip differential. The unit benefits through its high-torque progressive locking characteristics which provides maximum torque transfer in excess of skid torque.

The Visco-Lok operates through a self-contained silicone-fluid filled reservoir and shear pump that actuates a wet friction clutch pack. The pump generates pressure proportional to the speed difference between the wheels. The clutch pack actuates thereby transmitting torque to the appropriate wheel. The locking effect increases with the speed difference across the drive wheels.

This locking characteristic enables the Viper to accelerate well on surfaces with different friction conditions between the drive wheels. Additionally, GKN states that the Visco-Lok allows even better acceleration and less under-steer in cornering than compared to torque-sensing LSDs.

UNITRAX has installed many Visco-Lok LSD’s in Gen III SRT 10 Vipers, giving the SRT owner improved limited-slip performance and in our opinion a substantial upgrade over the Dana Spicer Hydra-Lok. The Visco-Loks have proven to be especially reliable in stock or modestly upgraded Vipers.

OS Giken Super Lock LSD

Starting with a blank slate, the talented engineer, Takuya Tomimatsu of OS Giken Co. Ltd. of Japan has designed the premier Dodge Viper SRT 10 LSD. Using the foundation of 4 years of initial Super Lock development and the world as a proving ground, OS Giken offers their highly respected and race proven OS Super Lock LSD for the SRT 10.

The OS Giken Super Lock LSD is more closely related to the disc-based TracLok LSD found in the Dodge Viper from 1992 through 2002. However, that is where the comparison ends. The revolutionary Super Lock is a true 100% locking LSD that instantly reacts and transitions smoothly from both free and locked positions, combining open differential drivability and limited slip differential performance and stability.

The OS Giken Super Lock features innovative technologies like the adjustable lock timing adjuster. Lock timing can be adjusted by replacing the springs in the pressure ring. Initial torque settings also adjustable through cone springs located at ends of clutch stacks. This allows the Super Lock to be tuned to meet your exact needs for optimum performance. UNITRAX is an authorized tune center and can discuss custom tuning to meet a driver’s specific requirements.

OS Giken is committed to producing an extreme quality LSD. Every Super Lock is manufactured from only the finest materials, regardless of the production cost. The Super Lock housing is manufactured from a proprietary billet steel alloy which is then heat-treated when finished. The side gears and pinion gears are hot forged and hand-finished. This attention to detail improves the precision and performance of the product.

U.S. patented bevel gear-in-pressure ring mechanism has enabled OS Giken engineers to miniaturize each gear, thus providing more space for up to an unprecedented number (28) of all-steel friction plates. The Increased number of friction plates improves the locking force of the LSD enabling it to lock fully and completely. An added benefit to being a fully locking mechanism is that less heat is generated, thus resulting in incredibly higher durability and reliability in even in the toughest racing environments.

OS Giken states that they have tested the Super Lock for over 22,000 performance miles and upon inspection of the unit, there was no wear, no loss of initial torque, and no loss of performance. UNITRAX inspected a Super Lock that was run for three full race seasons. The Super Lock showed no signs of wear and many of the components looked as if they had just come out of production.

The higher locking force provides outstanding straight-line stability at the drag strip. The Super Lock will lock to 100% and transfer torque equally to each wheel.

You will experience less under-steer during cornering. When entering a corner with the throttle closed, the spring inside the pressure control ring will react accordingly and immediately return the Super Lock to its original torque settings. When exiting a corner, the Super Lock’s transition to the 100% locked position is smooth and predictable, resulting in better traction, stability and quicker exit speeds. Additionally, racers and techs have reported that the Super Lock operates significantly cooler then competing LSD units.

One key feature separating the Super Lock from our other clutch type LSD’s is that with the Spec-S (standard) settings, the Super Lock is actually able to function as a open differential at low speed/low torque situations. Thus, when performing a normal slow speed turn (such as a right hand turn on the street) or backing out of a parking space, our differential functions as a normal open differential, allowing smooth turning without premature wheel lock. Of course with performance settings, such as drift which would require a much higher setting of initial torque, some premature locking may occur.

Unlike the Quaife ATB, the Super Lock does not require that the output shafts be drilled and modified. OS Giken engineered the unit to be center-weighted and the Super Lock ships with equal-length 41 spline performance output shafts! Due to the nature of the Super Lock design, featuring 28 all-steel friction plates, the driver may occasionally experience some disc chatter. To temper this characteristic, we recommended the use of O.S. Giken’s OS-250R 80w250 GL-5 synthetic lubricant. The disc chatter in no way affects the performance or durability of the Super Lock. Since the Super Lock runs cool and there are no contaminants from friction material polluting the lubricant, differential oil change intervals can be extended.

The Super Lock is used competitively in the U.S.A., Europe, U.A.E., Japan, Greece, and Australia. It also has a large and growing following in Autocross and Drifting circuits.

To date, there has not been one reported failure of the OS Giken Super Lock in any application. The engineers at OS Giken take extreme pride knowing that the owner of their LSD units compete with the utmost confidence.

The OS Giken Super Lock meets the needs of the most demanding driver who is comfortable with the way his SRT 10 feels with the stock Hydra-Lok or Visco-Lok but wants the tuneability, dependability, and durability that a fully race-engineered and manufactured LSD offers. The Super Lock is quickly becoming the preferred choice in the high-performance community.

If you have any questions regarding limited-slip SRT 10 differentials, please contact UNITRAX at 800.622.4327.


Copyright © 2011 by UNITRAX Drivetrain, Inc., all rights reserved.

Dec 122010

UNITRAX is looking for one high horsepower Dodge Viper SRT 10 to install OS Giken’s Triple Plate OS Racing clutch at a heavily discounted price. We are motivated to find a Gen III or Gen IV owner to work with.

Through OS Giken’s research and development of high performance engines, they realized the need for the production of higher quality, more durable clutch systems to meet the rigorous demands of race and sport driving. OS multi-plate clutches are able to transmit engine revolutions and output to the drive train without loss. They are made of the highest quality materials and their durability is second to none. OS Giken’s continual research and development has brought about many improvements since the multi-plate clutch line’s original debut in 1983 and they are confident that their clutches can meet the demands of even the most heavily modified vehicles.

Distinctive Features of the OS Multi-Plate Clutch:

In spite of its decreased diameter, our clutch allows for extremely efficient power transfer and improved engine response. OS Giken’s redesigned leverage mechanism of the diaphragm spring on the center cover results in higher pressure of the clutch disk while reducing pedal effort. In addition, ventilation holes are designed to reduce heat generated inside the clutch system and allows for the friction plate dust to exit outside the clutch system, thus increasing reliability and safety. All OS Giken clutches include a corresponding performance flywheel to ensure maximum performance and unlock your vehicle’s potential.

The estimated retail price on the SRT 10 OS Racing clutch is $3000.00.

Call UNITRAX at 800.622.4327 for more information on being the first to get this fantastic clutch at a one-time only price.