Tremec Tko500 And Tko600 5-speed Transmissions
Tremec is an OE transmission manufacturer that supplies manual transmissions for General Motors, Ford, Chrysler, Aston Martin, and many medium and heavy duty truck applications. Their TKO transmission is a high strength overdrive manual 5-speed that was originally designed to be retrofitted into Mustang Fox body cars to replace the weaker T5, but will also bolt up to the standard Ford four speed passenger car bellhousing. When Tremec realized that enthusiasts were adapting it for GM applications, they decided to capitalize on a huge opportunity and produce a GM version of the TKO as well.
The GM version will bolt directly up to almost any standard Chevrolet/Buick/Olds/Pontiac passenger car four-speed bellhousing. Though only Ford and GM versions of the TKO are available, Mopar enthusiasts can get all the custom parts they need to adapt a Ford version TKO to virtually any Mopar V8 engine from Keisler Engineering. The TKO has never been original equipment in any production car, although its great-grandpa, 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 a 32% overdrive ratio in fifth gear. The close-ratio TKO-600 is rated for a continuous 600 lb.-ft. of torque, and has a 2.87:1 first gear and either an 18% overdrive or a 36% overdrive ratio in fifth gear. The rated torque capacities 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 large margin, and failures are rare.
The TKO uses a three-rail internal shift mechanism, eliminating any external linkage and the adjustment issues that go with it. The short throw billet aluminum shifter can be removed, flipped 180 degrees, and then reinstalled to provide an additional shift position. Optional custom shifters are also available from Keisler Engineering in several different configurations to mimic the shift positions in various musclecars. The TKO utilizes cast iron shift forks, a one-piece counter shaft, and tapered roller bearings on the input, output, and counter shafts for added strength.
Every 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 wired into your vehicle’s existing harness. The transmission has an internal reverse lockout feature that prevents you from accidentally going from fifth gear into reverse. You have to go into the center of the “Neutral” gate before it will allow you to shift into reverse.
The Tremec TKO is an excellent choice for the musclecar, hot rod or street rod owner that enjoys shifting 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 a number of other cars with TKO transmissions installed. The overdrive makes a huge difference on the highway, and there aren’t many other overdrive transmission choices out there that will stand up to the kind of power that the TKO can take. None of the other overdrive transmissions available at this time offer as much versatility as the Tremec TKO.