Tremec is an OE transmission supplier manufacturing manual transmissions for Ford, General Motors, Chrysler, Aston Martin, TVR and many different medium and heavy duty truck applications. Its TKO is a heavy-duty 5-speed overdrive manual transmission that was originally designed to fit Mustang Fox cars to replace the weaker T5, but will also bolt to the standard hood of four-speed Ford passenger cars. When Tremec realized that enthusiasts were adapting it for GM applications, they decided to make it a little easier on people (and seize a great opportunity, too) by producing a GM version of the TKO.
The GM version will bolt directly to almost any standard Chevrolet/Buick/Olds/Pontiac passenger car four-speed hood. Although only Ford and GM versions of the TKO are available, Mopar enthusiasts can get all the custom parts they need to adapt a Ford TKO version to virtually any Mopar V8 engine. The TKO has never been original equipment equipment in any production car, although its great-grandfather, the Tremec TR-3550, was in a limited production Ford Mustang Cobra in the mid-1990s. The TKO is purely an aftermarket transmission. of accessories designed for high performance cars.
There are three basic models available, the TKO-500 and two variations of the TKO-600. The wide ratio TKO-500 is rated for a continuous load of 500 lb-ft. of torque, and offers a deep 3.27:1 ratio in first gear and a 0.68:1 overdrive ratio in fifth gear. The close ratio TKO-600 is rated for a continuous load of 600 lb-ft. of torque and has a 2.87:1 first gear and 0.82:1 overdrive or 0.64:1 fifth gear overdrive ratio. The torque ratings are said to be quite conservative, as there are a significant number of cars in the field with engines that exceed the torque rating by a wide margin, and failures are rare.
The TKO uses a three-rail internal shifting mechanism, eliminating any external linkage and the problems that come with it. The short-throw billet aluminum shifter can be removed, rotated 180 degrees, and then reinstalled to provide additional shift position. Optional custom shifters are available in several different configurations to mimic the shift positions on various musclecars. The TKO uses cast iron shift forks, a one-piece countershaft, and tapered roller bearings on the input, output, and countershafts for added strength.
Each TKO transmission provides both mechanical and electronic speedometer outputs. The mechanical output is a Ford design, but you can get hybrid speedo cables for GM or Mopar applications. They also feature a reverse light switch and a neutral safety switch that can be plugged into your vehicle’s existing harness. The transmission has an internal reverse lockout feature that prevents you from accidentally shifting from fifth to reverse. You have to go to the center of the “Neutral” gate before it will allow you to shift into reverse.
The Tremec TKO is a great choice for the musclecar or street rod owner who enjoys rowing his own gears and wants to drive his car to distant car shows or other events. I have one in my 1967 Pontiac Firebird and have driven several other cars with TKO transmissions installed. Overdrive makes a world of difference on the highway, and there aren’t many other overdrive transmission options that will hold up to the kind of power the TKO can handle. None of the other overdrive transmissions available right now offer as much versatility as the Tremec TKO.