Shifting Six With Confidence

LS1s can be built to make tons of horsepower and torque, and usually the clutch or the rear fails first once the power is put to them. So many install a 12-bolt rear and upgrade the clutch, but what about the transmission? Sure the wonderful Tremec T-56 six-speed transmission is a strong unit that can handle quite a bit more torque than Tremec rates it for, but any unit can be improved. So what do you do to ensure proper shifting and long life with 750-800 hp and as much as 600-700 lbs.-ft. of torque on tap? We went to the source find out and, in this case, it was Michael Weinberg and Brian Johnston and their company Rockland Standard Gear, Inc.

Rockland specializes in manual transmissions and can build just about anything to withstand the rigors of racing. Weinberg is a race car driver and has competed since the 1950s at such hallowed tracks as Lime Rock and Le Mans. Through racing experience and diligent research, the company has improved the six-speed transmission's durability and performance in all of its applications including the F-body, the Mustang, the C5 Corvette and the Viper.

For this story we will concentrate, of course, on an F-body trans. As stated, the T-56 is already a very rugged box. Neither gears nor any other major parts will need to be updated for racing. In fact, the improvements are mostly for the shift components and they are pretty straightforward, as you will see.

While the parts in and of themselves are not too exotic and the required measurements aren't too difficult, you will, however, have to completely tear down the trans to install the upgraded pieces. Mike suggests that you do not attempt this at home since specialized tools are needed to do the job correctly and the price for a few of them is prohibitive unless you plan to rebuild six-speeds for a living. Though I rarely advise readers to keep their hands clean, here, you are probably better off.

To that end, this will not be a nut and bolt swap as the procedures could and have filled a book. Many pages are dedicated to the T-56 in the GM transmission repair manual. We will instead take you on a tour to aid in identifying the trans and its outward components. Then we will highlight a few of the great technical features of the T-56, point out areas in which to look for trouble and perform the upgrades. So follow along with the photographs and refer to the exploded views often to see how everything works together.

Photography by the author
Diagrams courtesy of GM
Charts courtesy of Transmission Technologies Corporation

ABOUT ROCKLAND STANDARD GEAR AND ITS OWNERS
Mike Weinberg, one of two partners in Rockland Standard Gear, has been racing since 1957. He started in midgets and has been through all the chairs, drag racing, road racing, and he is currently driving a Vette in the Grand Am Cup series, the road-racing arm of NASCAR for Powell Motorsports, where his team has won four championships in the last five years. Weinberg holds seminars around the world for the transmission repair industry and provides tech support over the phone for Rockland's customers.

Brian Johnston, the second partner in the business, has developed the company's inventory computer system and he tracks the various upgrades and changes made to a bewildering array of transmission models. He ensures that Rockland is always prepared to serve its customers promptly and expertly, and provide the latest written technical information packaged with their orders.

Rockland Standard Gear started in 1981 distributing manual transmission and drivetrain parts, and remanufactured transmissions to dealers and the repair industry from a 2,000 square foot facility with Mike Weinberg and Brian Johnston as the principle owners. Over the years, the company has been involved with a lot of race teams and large firms like Gale Banks and Lingenfelter, which has provided valuable research in improving both the components and transmissions that the company sells. A free flow of information back to the manufacturers has also resulted in improved OEM designs.

Rockland tests the parts that it receives from suppliers on a regular basis to make sure that the quality is there initially and that it doesn't degrade over time. Specifications are compared to those housed in the company's computer system. An outside lab with the proper test equipment, including a profilemeter among other machines, is employed to do the testing.

Today, Rockland Standard Gear calls a 66,000 square foot facility home, has a client list exceeding 12,000 and provides parts and transmissions and most importantly technical support to all of North America, Europe, parts of Africa, the Middle East and down under in Australia.