Tremec TKO Transmissions Part 1 – TKO-500 and TKO-600 Features and Background
Tremec is an OE transmission supplier that manufactures 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 be retrofitted to Mustang Fox bodied cars to replace the weaker T5, but will also fit the standard bell tower of four-speed Ford cars. When Tremec realized that enthusiasts were adapting it for GM applications, they decided to make it a little easier for people (and seize a huge opportunity too) by producing a GM version of the TKO.
The GM version will directly fit almost any standard Chevrolet / Buick / Olds / Pontiac four-speed steeple for passenger cars. Although only the Ford and GM versions of the TKO are available, Mopar enthusiasts can get all the custom parts they need to fit a Ford TKO version to virtually any Mopar V8 engine. The TKO has never been original equipment on 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. 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 500 lb.-ft. of torque, and offers a deep 3.27: 1 first gear ratio and 0.68: 1 overdrive ratio in fifth gear. The close-ratio TKO-600 is rated for 600 continuous lb.-ft. of torque, and has a 2.87: 1 first gear and 0.82: 1 overdrive or 0.64: 1 overdrive ratio in fifth gear. 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 accompanying problems. The short throw billet aluminum shifter can be removed, rotated 180 degrees, and then reinstalled to provide an 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 speedometer cables for GM or Mopar applications. They also feature a reverse light switch and a neutral safety switch that can be connected to your vehicle’s existing harness. The transmission has an internal reverse lockout feature that prevents you from accidentally shifting from fifth gear to reverse. You have to go to the center of the “Neutral” door before it allows you to reverse.
The Tremec TKO is a great option for a musclecar or street rod owner who enjoys rowing with his own gears and wants to drive his car to car shows or other far-off events. I have one in my 1967 Pontiac Firebird and have driven several other cars with TKO transmissions installed. Overdrive makes a big difference on the road, and there aren’t many other overdrive transmission options that can withstand the kind of power the TKO can take. None of the other overdrive transmissions available at this time offers as much versatility as the Tremec TKO.