The T-56 Tremec 6 Speed transmission with the 2.66:1 first gear like used in the 2003/2004 Supercharged SVT Cobra's will be an absolute pleasure to drive. It seems to have a right gear for just about anywhere you find yourself.
Don't think of it as a 6 speed, think of it as a 4 speed with two overdrives — which is what it really is. The gear spacing is very attractive and the transmission in OEM form is stunningly strong. If it has a weak point it is the input shaft and Tremec offers a 23 spline large diameter upgrade that most of the performance crown has installed.
This is what one looks like;
The actual trans above is the T-56 Magnum and has much wider gears than the non-Magnuml T-56. Tremec no longer shows the non-Magnum T-56 on their website so the Magnum is likely the only game in town today.
The T-56 Magnum is rated at 700 ft/lbs of torque. It is a brute and they used an impressive triple cone synchronizer on the transmission. When you shift even at 7500 rpm it is like a hot knife through butter. Another benefit of the Tremec Magnum version is the availability of five different gear ratios, The first gear offerings are, 2.97 and 2.66 from Tremec. Rockland gear offers three special 9310 nickel steel Tranzilla gear sets cut at a 22˚tooth angle with first gear ratios of 2.98, 2.71, 2.62 and 2.29.
The Rockland gears used in their Tranzilla 6 speed are rated as 1000 ft/lb of torque gear sets if you use a Viper mainshshaft. You can get a used normal T-56 and buy the Rockland gearset and come out about the same as a new Tremec. The difference is the 2.62 and in particular the 2.29 gear sets.
The 2.62 is a very nice close ratio set pretty evenly matched between gears. The 2.29 gear set is (rpm drop-wise) like the gear sets used in the large diesel tractors where you hear the engine sound like it has the exact same rpm drop between every shift. The 2.29 gear set is a to die for gear set. You won't need the strength but you'll love changing gears — magnificent doesn't do it justice.
If you go the TKO 600 route you need to get Liberty's shift rail timing upgrade, the carbon fiber synchronizers and the countershaft front bearing modification. The front bearing mod is reliability, the other two are shift quality.
If you go the TKO route definitely get the 0.82 overdrive unit. The transmission is sometimes referred to as the Road Race version. The 0.64 overdrive is not as nice a driving experience because of the big gulp from 4th to 5th. With the 0.82 OD the gear change just feels like the next gear — much nicer driving experience.
This is a pic of the TKO;
Although the other transmissions are period correct they do not provide as good a driving experience. The 6 speed T-56 is by far the best driving experience of all. It just feels like you always have the perfect gear ready for any road condition you encounter.
I have a Liberty modified 0.82 OD Tremec TKO600. The difference in shift quality from an OEM Tremec TKO is nothing short of stunning. That said, the way Tremec and the aftermarket have developed the T-56, I wish I had a T-56 today — which I may convert to anyhow.
If you like the shifter positioning of the 2xxx generation Cobra's shift lever, either the TKO or the T-56 transmissions offer a mid shift position that will closely duplicate the original shifter position.
Ed
10Likes
Hybrid Mode
