|   OEM  Aftermarket  Ratio
        Change  Positraction 
        Custom Housings  Musclecar  Heavy Duty 
        Light Duty And Passenger  High-Performance 
         OEM (Original Equipment Manufacture) 
        OEM is used to designate replacement parts which are
        sold as dealer parts through Ford, GM, Chrysler, etc. OEM parts are well crafted and
        expensive. They are not always the best choice, but sometimes they are the only choice. 
        Aftermarket 
        Aftermarket parts are replacement parts that are not
        manufactured or sold as OEM. This does not mean it is not a quality part; it simply is not
        OEM. 
         Ratio Change 
        A ratio as it pertains to an automotive application is
        most easily explained as the number of turns of the rear or drive wheels in relation to
        the number of turns of the engine. Basically , this is governed by a gear set in the rear
        axle of the car or truck. If the engine is considered the input and the drive wheel is
        considered the output, then the input gear or pinion meshes with the output gear or ring
        gear to drive or rotate it. The number of teeth on each gear determines the ratio. For
        example: A pinion gear may have 15 teeth that mesh with a ring gear that has 45 teeth;
        mathematically (45/15) this yields 3.00 ratio. That means that the engine will turn 3.00
        times for each turn of the drive wheel. This is generally thought of as a high or highway
        ratio, even though it is low numerically. Common ratios in use today range from 2.29
        through 6.50. 
         Positraction 
        Positraction is a term that is used in a vague sense,
        almost generically; something like asking for a coke when you want a soda (not necessarily
        a coca-cola)...in its general interpretation, a posi is a device engineered to rotate or
        drive both wheels with the same force (forward or back). As opposed to an open
        differential which allows the wheels to turn independently, even without drag in opposite
        directions if need be. Open differentials were created to allow an axle to negotiate a
        curve; after all, the wheel on the inside of the turn navigates a shorter path than the
        wheel on the outside. Otherwise, one wheel would drag or skip along the road if the axle
        was a rigid non-flexing unit. If conditions on a road were always perfect (as in dry,
        flat, uniform texture, etc.), then an open differential would be all that was needed. Now,
        consider dirt roads and potholes: It is easy to see the need for both wheels to drive as
        if the axle was rigid. Enter posi units...without getting complicated, the posi acts as a
        clutch between the two drive wheels, allowing the wheels to turn independently, but at the
        same time exerting a drive force on both. This is helpful on dissimilar surfaces such as
        sand, gravel, or mud because if one wheel is slipping, the other can still be counted on
        to provide drive force. Otherwise, without that drive force, the vehicle will, of course,
        be stuck. There are many different designs of positraction units (some are better than
        others); the main difference is the amount of friction (at the tire contact path) required
        to cause them to clutch or allow one wheel to turn independently. Off-road, heavy duty
        towing and hi-performance vehicles place great demands on traction units. 
         Custom Housings 
        Custom means "Made To Order"...We can
        fabricate a custom housing from scratch or retail a pre-made assembly. A rear end housing
        is the shell or case that houses the axles, brakes, differential, gears, and the oil that
        keeps it all lubricated. The need for custom housings arises when the original can't fill
        the bill, either because of strength, size, parts availability, or all of the above.
        Naturally, hi-performance and 4WD off-road vehicles come to mind. Both applications are
        hard on original parts. The 9 inch Ford, Dana 60, and 12 Bolt GM are the most commonly
        custom-built housings. The 9.0 Ford is popular in both hi-performance and 4WD; it has a
        good strength/weight ratio and is used mostly in racing applications where light weight is
        important. Also, due to its popularity, there are many aftermarket parts available for it.
        The Dana 60 (D60) is the strongest unit of the three. It too, is popular in racing, but
        its weight becomes a factor if the extra strength isn't warranted. The D60's forte is 4WD
        off-road, bracket race cars, and heavy duty towing applications where extra weight is not
        a hindrance. Last, but not least, comes the 12 bolt GM...It is prized for its light weight
        and good strength and, since it is custom, it uses stronger axles than the originals which
        are considered to be its weak link. It is used in hi-performance and off-road. Each of
        these units has good aftermarket and OEM parts availability. 
         Musclecar 
        Musclecar is unique in that it is a combination of high
        performance and passenger car that was manufactured and sold by the OEM's to the general
        public to be used on the nation's streets and highways just like any other car. It is
        highly prized by its owners. Some owners want absolutely OEM replacement parts
        (restoration) while others want high strength race car units or something in between. We
        offer both and have years of experience with these cars. Custom housings, axles, and
        differentials are prevalent on the race car end of the spectrum. New brakes help to bring
        it all to a halt. 
         Heavy Duty 
        Heavy duty is almost a contradiction of terms; it
        includes pick-ups and light trucks up to 1 1/2 ton chassis. These vehicles are actually
        light duty trucks as far as trucks are concerned. There is no high performance as such in
        this market, but bigger is better in these cases and if the original can't be made to hold
        up then a bigger unit is in order. Towing, places greater demands on a differential than
        normal, especially when getting off the highway is involved. The most common failure in
        heavy duty is parts breakage due to overloading. Ratio changes and positractions are the
        most common modifications. 
         Light Duty And Passenger 
        This category encompasses fully half of our service
        shop repairs. It includes 1/2 ton pick-ups and daily-driven automobiles. The majority of
        repairs are necessitated by collision and lack of maintenance. Some customers simply want
        positraction or a ratio change. Oil leaks are generally a sign of another problem, but
        some can be repaired without incurring further expense. A rear end is like an engine and
        transmission; it has bearings, seals, gaskets, and gears and they are all designed by the
        manufacturer to last through the warranty with normal service. Then it wears out. Owners
        of vehicles in this class usually want to repair their car as cheaply as possible. This is
        where aftermarket parts really shine. The labor to install the part is the same, but the
        part is sometimes 1/2 the cost of OEM and delivers, in most cases, the same
        serviceability. We have a large inventory of aftermarket and OEM parts stocked for this
        group and service of this nature usually takes only 1/2 day. 
         High-Performance 
        This group covers a wide spectrum of on and off-road
        vehicles. Generally assumed to be race cars, this group can include everything from
        mud-boggers (4WD) to FUNNY CARS and NASCARS and back to street driven musclecars. We
        handle the hi-performance market through both the service shop and our mail order office.
        We sponsor several high profile racers in the local area and some who appear on nationally
        televised events. Custom housings and axles are prominent here because strength and light
        weight are highly prized. Optional ratios are a common installation in drag cars and many
        musclecars. 
         4WD 
        4WD covers many segments of our basic line of services.
        In standard repair we do just that; we fix what's wrong with the service parts available.
        These can be specified as genuine OEM (dealer parts) at customer request and, although
        more expensive, in most cases (not always) these parts are higher quality...SUVS (Sport
        Utility Vehicles) and pick-up trucks comprise the majority of these type repairs. 
        Many customers want to make a ratio change. This
        usually involves removing the original ring and pinion (gearset) and replacing it with one
        of a higher numerical ratio. An example would be a change in an '85-'90 Chevy 1500 series
        pickup which commonly comes with a 3.42 ratio to 4.10 ratio. This change is usually
        necessitated by a switch to a taller tire. 
        Installing positraction is another common request. In
        4WD it can be installed in both front and rear, but is generally used in the rear only.
        There are many traction units to choose from. The main difference between them is their
        ability to withstand the rigors of offroad duty. Strength and expense are proportional
        here...another consideration is that as a traction unit becomes stronger for off-road it
        becomes less and less streetable. 
         3RD Members 
        Custom 3rd members are self-contained
        differential units which can be removed and replaced without taking the actual brake and
        housing assembly out of the chassis. They are all based on the 9.0 Ford because of its
        high-strength/weight characteristics (very popular in racing) and the unsurpassed
        interchangeability as compared to other designs. There are myriads of aftermarket parts as
        well as a good supply of OEM replacements. This form of differential has been around since
        the 1950's and is used in everything from Edsels to Pro-Mod racing machines. 
          
         
          
        2402 West Cbyo-Lynchbg Rd. 
        Baytown, TX  77521 
        281-421-5878
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