GForce GSR Dog Box 4-Speed H-Pattern
The G-Force GSR Dog Box is an ultra-high-strength 4-speed H-pattern racing transmission designed for serious motorsport applications, including drag racing, drifting, time attack, and rallying.
G-Force Transmission is known as a racing transmission manufacturer adopted even in NASCAR, the pinnacle of stock car racing in the United States. The technology forged in extreme conditions such as high temperatures and high loads is utilized in this GSR transmission as well.
A major feature of this GSR is that its 4-speed configuration allows each gear to be designed with a larger diameter and higher strength. As a result, it maintains stable durability even with high-output engines in the 700–1500 hp class. Furthermore, because it adopts dog-engagement gears rather than a synchronizer system, it allows for clutchless shifting / quick gear changes / and compatibility with high torque and high output.
Key Features
H-pattern shifting maintains the OEM feel
Dog-engagement gears for high-speed shifting and superior durability
Internal oil pump provides stable fluid supply during high-RPM, high-load driving
Dual-bearing center support / one-piece mid-plate structure reinforces case rigidity
32-spline output shaft compatible with high power
Selectable Shifter Offset (distance from the front of the transmission to the center of the shifter)
21 inches (approx. 53.3 cm)
24 inches (approx. 61.0 cm)
26.5 inches (approx. 67.3 cm)
Orders can be customized to fit your vehicle's transmission location and seat position.
Custom Gear Ratio Configuration
The GSR can be custom-ordered with an internal gear configuration from over 250 gear ratio options to match your vehicle's specs, intended use, track, engine characteristics, and tire diameter.
Do not worry if you are unsure which gear ratios are optimal. We have provided GSR dog boxes to many Japanese and American race teams and drivers, and we have accumulated a large amount of base data.
If you contact us in advance, we will propose the optimal ratios for your needs.
The standard available gear ratio chart can be viewed here.
Custom Input Shaft (separate additional cost)
14-spline Toyota 2JZ engine (for V160 bell housing)
24-spline RB / SR engine series
We also handle other configurations, such as 10-spline for other engines, as well as adapter plates to make installation easier, so please contact us separately.
Regarding the Output Shaft
All GSR output shafts are 32-spline.
We can also produce one-off propeller shafts tailored to your vehicle; please see here for details.
Purchasing Consumables
As an authorized G-Force dealer, we can supply all consumable parts, including transmission cases, individual gears, bearings, and snap rings. You can view the transmission parts diagram here.
Even if you did not purchase your transmission unit from us, you can still order individual parts, so please feel free to contact us.
Lead Time
This product is assembled by hand, one unit at a time, by technicians in the U.S. to meet various specifications. While we may have items in stock at our warehouse, if they are out of stock, it will take several weeks from order to shipment, so please inquire about lead times in advance.
Please contact us regarding lead times.
Before Ordering
〇 Import Consumption Tax
At Shafutoya, we cover the import consumption tax incurred at the time of import, so there will be no additional charges beyond the total amount paid at checkout.
〇 Verification of Compatibility
All product databases are based on North American vehicles (USDM). Please verify whether installation on a Japanese vehicle (JDM) is possible before ordering. (Please feel free to contact us if you are unsure if a listed product is compatible with your vehicle. Our support team will investigate for you.)
If you order without verifying compatibility, we cannot accept returns due to incompatibility.
Please note that even if items are sorted by selecting the model year, manufacturer, and vehicle model in the tabs on our homepage, it does not necessarily mean they are compatible with Japanese model vehicles without modification.
All products have been translated into Japanese using translation software. As there may be confusing expressions, please contact us before ordering if you have any questions.
○ Regarding Shipping
Shipping costs are paid at the time of checkout. Shipping estimates are automatically calculated by entering your shipping address on the checkout page. For large items such as body parts, the automatically calculated shipping cost may rarely differ significantly from the actual shipping cost. In such cases, we will contact you individually via email.
All products are generally shipped internationally from our U.S. warehouse. Unlike domestic Japanese shipping, international shipping takes about 7 to 14 days, so please order with sufficient time. If you are in a hurry, please contact us to check lead times in advance. All products are transported via air freight. They are not shipped via sea freight.
○ Regarding Japanese Vehicle Inspection (Shaken) Compatibility
All products we handle are designed and manufactured outside of Japan. Please note that they do not conform to "Japanese vehicle inspection standards," and we cannot provide documents such as structural strength analysis reports for Japanese inspection purposes. Therefore, all parts are sold for the purpose of "use on circuits, private property, and off-road," and installation and use are at your own risk.
○ Regarding Warranty
Please inspect the contents immediately upon arrival. As all products are shipped internationally from outside Japan, there may be shipping damage to the packaging or the product itself. Please understand that we only provide returns, refunds, or replacement support for products with shipping damage, defective items, or items different from what was ordered if you contact us within 7 days of receipt. Furthermore, for products sold through us, warranty-related support will be handled "exclusively through us." Please note that we do not provide support through other companies or distributors located in Japan.