LS1GTO Forums banner

New SEQUENTIAL 6-speed!!!

8363 Views 5 Replies 3 Participants Last post by  LT1Brutus
One of the companies we've been working with in Australia is ready to release their direct bolt-in T56 replacement. Aside from the benefit of sequential shifts, the tranny can also handle DOUBLE the torque rating of the T56. This will work in GTOs, F-bodies, and Vipers, and we will be working with the manufacturer to see if we can get it to work with the transaxle in the C5 as well. Here's some information about the unit:
Torque rating: 800 ft/lbs. (constant load)
Gear Ratios: 1st- 2.692
2nd- 1.972
3rd- 1.466
4th- 1.195
5th- 1.000
6th- 0.842
All indirect gears are mounted on splines so that ratio changes can be made economically. 1st and 2nd gears have double cone syncromesh. Heat treated nickel chrome steel is used for all gears and the gear profiles are ground on a Reishauer machine after heat treatment. The selector forks are aluminum bronze alloy. The casings are cast LM25 aluminum alloy heat-treated to T6 specs. The clutch splines are normally 1 1/8x 26 24/48 DP x 30 degrees PA.

The gear lever is pulled back for up changes and pushed forward for down changes. Neutral is selected from 1st gear position by moving the gear lever to the left and forward. Reverse is selected from the neutral postiion by pushing the gear lever forward. From the reverse gear postion, neutral is selected by pulling the gear lever back and 1st is selected by pulling the gear lever back again. This system eliminates neutral or reverse being accidentally selected when in the forward gear change pattern.

A cam shaft performs the gear change with hydraulically assisted cam followers to ensure low effort gear lever movements. The main shaft, input shaft and lay shaft are mounted on taper roller bearings straddling 3rd, 4th, 5th and constant mesh gears.

Preload is easily adjusted with spacers behind the front cover. First and second gears are in the rear housing with the extremities of the shafts supported by needle bearings.

Pricing is not finalized but don't expect this to be the next "everybody's got one" bolt-in. Rough estimates on intial pricing are in the $10,000 USD area, but should come down as production ramps up. Anyone planing on building a serious race vehicle with a T56 will benefit hugely from the addition on this gearbox assuming it meets class rules. We expect 9.0-9.2 second quarter mile f-bodies will finally be able to consistantly break into the 8.9 bearier from the flawless shifts this tranny will allow. Road-race and autocross vipers, f-bodies, and GTOs will be able to effortlessly click through gears, never missing a beat which will decrease lap times, decrease driver effort/fatigue, and increase consistency between laps.
See less See more
1 - 6 of 6 Posts
Toughguy, this is not a fully automatic manual. You will still have to operate the clutch**, sorta. Though we recommend using the clutch for ALL gear changes, you can physically change into each ascending/descending gear after you have used the clutch initially to get into 1st gear from a stop.

As for skipping gears, you could do it 2 ways. If you were ALL OUT racing and not utilizing the clutch for shifts you could just rapidly shift through the gear you wished to skip. Alternately, you would push in the clutch, pull the lever twice (that would skip one gear), and then let the clutch out again.
Kinda almost like a hydrostatic unit in a tractor or something. Lexus also uses a 6 speed sequential shift unit. Is it the same?

Man, that is a tall 1st gear! 2.69:1...DAMN!!! The stock T56 si what 2.6:1

But that torque rating is nice. :D

How much?
No this is not the same as the unit in the Lexus. It was specially designed to replace the T56, offering incredible torque managment, low power loss, and yet still offering streetable amenities such as helix-cut gears rather than going absolutely all-out race with straight cut gears.
Tuffguy, if it makes you feel any better the stock clutch is "hydraulically assisted":D . If you really want to slap the $$ down I'm sure we could get your transmission a computer controlled hydraulic clutch actuator and we could make it sit pretty, roll over, and play dead.....oh no, on 2nd hand w/ a torque rating of 800 ft./lbs. it couldn't even play dead
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.