A Short Guide to Aftermarket Transmission

The automotive aftermarket parts industry is seeing a boom nowadays, with rise of the online medium making replacement or custom parts more easily available for the consumers. Transmission kits and parts in particular are some of the most sought-after aftermarket parts; transmission problems can significantly hinder the driving experience and even functionality of the automobile.

There are a plethora of problems that can happen with both manual and automatic transmission such as fluid leaks, gear slipping or a dragging clutch. Depending on the severity, it might come out cheaper in the long run to replace the whole transmission system from bottom to top. At the same time, you may want to change your CVT Honda Civic to a classic gear-based output, or upgrade your 4-gear manual to a 5 or 6-gear. Or maybe building a lightning fast hot-rod from scratch is your childhood dream which you now hunt to fulfill.

In any case, it’s for the best to have some basic knowledge about who provides what before shopping for new transmission parts. Certain aftermarket suppliers are linked with automotive producers and can offer official replacement parts, whilst others can offer a more varied selection. The transmission market is one of the most open from this point of view, if only for the large array of different types and parts available.


ACDelco is one of the oldest automotive producers, which is due to celebrate its 100th birthday next year. Now, Delco functions in two ways: it offers factory pieces for General Motors vehicles and also offers a wider assortment of aftermarket parts unrestricted to owners of GM cars. These include batteries, alternators, spark plugs and air filters, amongst others.

As far as transmission parts go, there’s not much to go by as full transmission sets are restricted to General Motors original equipment. So this is the place to go if you need replacements for second generation GM automatic transmission, for either front or rear-wheel drive. The manual transmission assortment is wider, ranging from 3 to 7-speed from Aisin, Muncie, New Venture Gear or Tremec.

Outside this, Delco does offer its own minor parts to non-GM vehicle owners, such as transmission filters that protect pieces from long-term contaminants, and some own assortments of transmission fuel.

American Powertrain

At the opposite end of aftermarket providers to Delco sits Tennessee-based American Powertrain, which is specialized in overdrive transmission systems and drive-train sets for high speed muscle cars and hot-rods. Entering its 10th year of existence, it’s probably the place you’ll want to know about if you want to make your decades old Mustang ready for race events. AP also offers racing support and rebuilding services for supported transmission sets. Their custom overdrive sets are based mostly on Tremec systems, varying between 5 and 6-speed systems, and you can buy them separately or in bundles called Pro Kits.

Dana Corporation and Spicer

Not to be confounded with the Texan Mark-Dana real estate company, Dana Corp. is one of the biggest players in the automotive powertrain aftermarket. Based in Toledo, Ohio, the company deals with supplying axles (such as their vastly used Spicer 5-760X), driveshafts and suspensions to automotive manufacturers worldwide, spreading its pieces to such locations as Paris, Glasgow or Lima. They are also some of the biggest employers in the domain, with over 23.000 jobs occupied throughout more than two dozen countries.

As transmissions are concerned, Dana Corp. deals almost exclusively in off-highway transmission, with its Spicer OE brand offering everything from transfer cases to hydrostatic gear boxes.These are of course best suited for heavy industrial and agricultural machines such as tractors, combines or bulldozers. Spicer provides various configurations of Powershift Automatic and Dual Cluth – type transmission, with the buyer having the choice of it being mounted directly on the engine, above it or even remote from it to offer more flexibility.

ZF Group

South-West German manufacturer ZF is somewhat an European counterpart of Delco, with it reaching its centenary this year. Their North-American service centers should be what you’re searching for if you own a European vehicle, with their own vast range of manual and automatic transmissions being used by a variety of manufacturers around the continent. ZF transmissions are particularly interesting in their automatic form, with their 8 and 9-speed automatic being not being replicated by GM as of yet.

Almost any of these systems’ specific parts are available on their own, so if you’re searching to inject more mileage at low-cost maintenance then you’re in luck. Besides this, repair kits for DIY enthusiasts and a range of ZF-exclusive transmission oils cap off quite an impressive and varied offering that the German manufacturer gives to users of their products. They also use rebuilt pieces in some cases as OE replacements, which should score some points with green movements.

TCI Transmissions

Initially starting off as a provider of performance transmission sets for drag racing pros and enthusiasts, TCI Auto is now mainly supplying aftermarket max performance street gear. If you’re searching for a monster transmission set, it’s most probable that their Super StreetFighter 700R4 will make you stop shopping and start paying, with its capability of handling 1000 HP and overly-increased Torque capacity.

TCI Automotive is known for providing some of the highest quality torque converters around any aftermarket suppliers, and also offer repair services for these and transmissions regardless of their manufacturer. Automatic service of this kind is offered for a range of GM, Chrysler, AMC and Ford (including C4 and C6) transmissions.

These are just a number of the biggest and more specialized aftermarket suppliers for transmission and powertrain elements in general. There are literally hundreds of chain shops and retailers nowadays for customers to choose from, and searching for specific replacement parts can get confusing and frustrating, and the temptation of leaving your car transmission’s fate in the hands of the nearest local amateur garage probably grows higher because of it. But like it is the case with many things, patience is rewarded in car maintenance as well.

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