ScienceofSpeed offers custom built 5-speed transmissions. We pre-build transmissions using transmission cores or units built using the transmission you provide. Please read about our core exchange program if you wish to have a transmission pre-built for exchange.
Each transmission is fully rebuilt using all new factory synros, bearings, spring rings, oil seals, and snap ring (the rebuild parts can be found here). Each transmission is blueprinted during assembly for durability and consistent smooth shifting operation.
There are three types of modifications that can be made to the transmission:
- close ratio gears: the individual gear ratios are modified which allows the engine to maintain optimal powerband during shifting improving acceleration. Japanese version NSXes are equipped with transmissions with close ratio gear sets. Unlike the US version transmission, the car will not fall out of VTEC and optimal powerband. These gears can be installed into a US-spec transmission. Factory Honda parts from Japan are used.
final drive gear set: As the power is transmitted through the transmission, the last set of gear set that transmits the power to the wheels is the final drive assembly. The final drive gear ratio is consistent for every gear the car is in. The US factory gear ratio is 4.06:1. The Japanese performance version of the NSX uses a 4.23:1 gear ratio. This gear set consisting of the countershaft, differential ring gear, and oil gear can be installed into a US-spec transmission. Factory Honda parts from Japan are used. The NSX-R spring plate and collar is included to set the pre-load to NSX-R spec. (more info)
A higher ratio final drive gear set is available (4.44), however, it is only compatible with the OS Giken differential.
differential: OS Giken offers an innovative Super Lock Differential which combines a helical gear type and clutch plate differential. The gear design allows maximum power to be transmitted to the inside wheel for improved corner traction while the 28-plate clutch pack allows for smooth torque transfer improving stability of the car and smooth operation. (more info)
We offer several options for 5-speed transmissions:
- fully rebuilt US spec 5-speed transmission: all new factory syncros, bearings, spring rings, oil seals, and snap ring parts are replaced. Transmission is blueprinted and ready to be installed once delivered. Available for 1991-1996 5-speed manual transmissions.
- short-ratio: fully rebuilt transmission with Honda JDM Short Gear set installed. Available for 1991-1996 5-speed manual transmissions.
- short-ratio / NSX-R 4.23 final drive: fully rebuilt transmission with Honda JDM Short Gear set and Honda NSX-R 4.23 ratio final drive. Available for 1991-1994 5-speed transmissions. 1995-1996 transmissions require a torque control differential, available separately (please inquire).
- OS Giken LSD: The OS Giken LSD, in either the factory 4.06:1 ratio or the OS Giken 4.4:1 ratio may be added to either dpp-211 or dpp-212.
Transmissions are shipped by our freight carrier. Shipping total includes palletizing.
Packages include parts & installation. ScienceofSpeed offers the following custom 5-speed transmissions on exchange through our core exchange program allowing for zero down time. Customer may also provide 5-speed for customization. Installation into vehicle is extra. Please note: transmissions in snap-ring range require replacement of the transmission case half.
ScienceofSpeed Core Exchange Program:
ScienceofSpeed offers a free core exchange program for this product. You will be charged a refundable deposit on check out. Once you receive the product, return your core to ScienceofSpeed within 30 days from date of receipt for a refund. For full details, please click here.