All in all, the T56 in your C5 or C6 is a good transmission. However, when you get serious about racing but want to keep a manual gearbox in your Corvette, there’s no doubt that you’ll need to start looking at other options. There are plenty of transmission rebuilders out there who can give your T56 more torque capacity, but if you need or want a true max effort race transmission it’s hard to find a better option than the LG/Emco Sequential 6-Speed gear box.
A couple years ago LG Motorsports teamed up with the race transmission builders at Emco to provide a tough sequential 6-speed option to C5 and C6 owners.
Recently LG Motorsports posted this “inside look” at the sequential gear box on Corvette Forum, along with plenty of pictures and tech info. The thread really got our gears turning, so we called up our friend Anthony Forney at LG for some more info on this purpose built 6-Speed. “Emco builds these transmissions from the ground up with straight cut gears, replaceable dog rings, full roller bearings, and a pressurized oil system,” Forney tells us. “All the gear ratios are customizable, and there are around 40 different combinations you can put together depending on your Corvette’s characteristics.”
True to its name, the Sequential 6-Speed eliminates the common H-shift pattern, and shifts are made by simply bumping the shift lever up or down, meaning no missed shifts. The shift pattern is changed to a linear R-N-1-2-3-4-5-6, with a mechanical reverse lockout so you can confidently fly through downshifts. Best of all, there is no need to use the clutch for either up or down shifts with the proper technique. Forney tells us, “You just need to get the dog rings to unload, if they are loaded they won’t disengage. You just lift off the throttle, the gears will unmesh, and you can shift. Then you will only need the clutch for start and stop. With the right spark-cut electronics and programming you can just flat shift, and don’t even need to lift or blip the throttle to shift.” (If you’re really interested in this capability, give LG a call and they can fill you in on the details.)
Probably one of the most interesting parts of the LG/Emco Sequential 6-Speed is the fully pressurized and filtered oiling system. The main shaft and shift forks are gun-drilled for oil passages, and a spray bar provides a steady supply of oil directly to the teeth of the gears. “The oiling system is set up essentially like an engine and creates between four and 12 PSI. The oil pump even works like a mini LS1 pump, but the system only uses two quarts of synthetic 75W90.”
Even the shift forks and main shaft are gun drilled for pressurized oil passages.
So what is the power rating on this bad-boy? LG says you can expect the Sequential Gear Box to handle around 1,000 pound feet of torque. Given that these are essentially the same gear boxes used in the Grand Am GT Class Corvettes and even the Daytona Prototype Corvettes, you know they’ll have the reliability to match that power rating.
Here you can see the spray bar that keeps a steady flow of oil on the gear cluster at all times.
The LG/Emco gear box is a direct upgrade for the C6 ZR1 and Z06, and C6 base cars and C5s require an upgrade to the Z06/ZR1 differential as well as the use of an adapter plate. As an added benefit the gear box is about 25 pounds lighter than the Corvette’s stock T56. The transmission is designed first and foremost for racing, but if you’re willing to live with its quirks, there’s no real reason you couldn’t use one in a street car. In fact, as you can see from the video above, Lou Gigliotti uses one in his personal Z06 street car.