SpeedTekAutoRacing 10-inch Quick Change Differential
Built for Power. Crafted for Precision.
Product Overview
Capable of handling over 1000 HP.
Speedtek's Quick Change Differential is engineered to deliver overwhelming durability and performance even under the most grueling conditions, utilizing top-quality materials and precision machining processes.
A product designed for those seeking a reliable drivetrain for extreme motorsport competition, such as Time Attack, drifting, or drag racing.
Since the mounting points are identical to the Winters and DMI BullDog 10-inch Quick Change, it is compatible with existing rear members currently using Winters units.
Key Features
■ A356-T6 Gravity Cast High-Strength Housing
Designed for high rigidity and strength.
Precision-machined finish ensures high case rigidity and exceptional durability.
■ 6082-T6 Forged Billet Aluminum Side Bell Housing
Forged design boasting high rigidity, suppressing housing and case deflection even under high loads and high torque.
■ 4140 Chromoly Steel 1350 Series Front Yoke Flange
Ensures drivetrain reliability while supporting high-output engines.
■ 300M Billet Steel Main Shaft
Balanced and precision-machined for superior torsional rigidity, strength, and rotational stability.
■ 4340 Forged Billet Steel 35-Spline Side Flanges
Compatible with Porsche 930 standard (108CV) or Nissan 6x1 bolt pattern (GT-R / Z33).
・The Nissan 6x1 bolt pattern allows the use of stock driveshafts from vehicles like the GT-R and Z33.
■ 7075-T6 Forged Aluminum Center Spool
35-spline forged spool configuration, the key to traction.
Built to withstand the most demanding operating environments.
■ 8620H Steel Crown & Pinion Gear Set
Precision-cut for a balance of quiet operation, wear resistance, and smooth performance.
※ Gear sets from Winters / DMI BullDog differentials are also compatible with this Quick Change unit.
■ 6061-T6 Billet Rear Differential Cover
Integrated cooling fin design.
Built-in oil level plug for quick and easy oil management and changes.
■ Wheel Speed Sensor Compatibility
Supports accurate wheel speed data acquisition, useful for data loggers and gear ratio selection.
■ Multiple Sensor Ports
Allows installation of temperature sensors for real-time monitoring.
Helps maintain optimal performance and durability.
■ High-Quality Bearings & Oil Seals
Uses top-tier bearings from brands such as Timken, NSK, and SKF.
Ensures stable long-term use even in high-load environments.
■ Zinc-Plated High-Strength Grade 10.9 Metric Bolts
Uses the highest strength mounting bolts for all critical points to ensure safety and reliability.
Optional Configurations
■ Lightweight 8620H Billet Steel Ratio Gears (Optional)
Available Gear Ratios:
3.1 / 3.3 / 3.5 / 3.7 / 3.9 / 4.1 / 4.3 / 4.6
ISOTROPIC SUPER FINISHING (ISF) Available
For those seeking even greater performance and durability.
■ Skid Plate (Optional)
Provides enhanced protection for the underside of the differential against road debris.
We offer a variety of final gear sets, allowing for gear ratio changes in just minutes.
This quick change unit is also compatible with Winters gear sets.
Shafutoya stocks a large selection of skid plates for quick change units. Skid plates are an essential item for quick change differentials, as they protect the diff case from breakage or surface damage due to road contact.
We also provide custom one-off driveshaft fabrication for SpeedTek / DMI BullDog / Winters Quick Change units. Learn more here.
Both of these quick change types use 1350-series differential flanges. We strongly recommend the use of Mark Williams billet U-bolt kits.
Pre-Order & Delivery Information
Pre-order pricing is limited in quantity.
This promotional pre-order pricing ends once the initial production run of 300 units is sold out.
Expected Shipping
Spring 2026 (Shipping dates are subject to change without notice. Please note that pre-orders cannot be canceled).
Maintenance Interval
Recommended annually.
Warranty
Unconditional 6-month warranty.
International Shipping
Shipping costs are included in the product price.
Before Ordering
〇 Regarding 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 Compatibility Verification
All product databases are based on North American (USDM) vehicles. Please verify compatibility with Japanese (JDM) vehicles before ordering. (If you are unsure if a product fits your vehicle, feel free to contact us. Our support team will investigate for you.)
If an order is placed without verifying compatibility, we cannot accept returns due to fitment issues.
Please note that even if products are sorted by year, make, and model using the tabs on our home page, this does not guarantee direct bolt-on compatibility with Japanese-spec models.
All products have been translated into Japanese using translation software. Due to potential phrasing ambiguities, please contact us with any questions before placing your order.
○ Shipping
Shipping costs are paid at the time of checkout. Estimates for shipping are automatically calculated once you enter your shipping address at checkout. For large items like body parts, there may occasionally be a significant discrepancy between the automatically calculated shipping cost and the actual cost. In such cases, we will contact you via email.
All products are generally shipped internationally from our US warehouse. Unlike domestic shipping in Japan, international shipping takes approximately 7 to 14 days, so please allow ample time for delivery. If you are in a rush, please inquire about lead times beforehand. Please note that all items are shipped via air freight; we do not use sea freight.
○ Regarding Japanese Vehicle Inspection (Shaken)
Our products are generally designed and manufactured outside of Japan. Please note that they are not compliant with Japan's "Shaken" vehicle inspection system, and we cannot provide strength evaluation documents or similar certificates for this purpose. Therefore, all parts are sold for "circuit, private property, or off-road use only." Installation and usage are at your own risk.
○ Warranty
Please inspect the contents immediately upon arrival. As all products are shipped internationally, there is a possibility of shipping damage to the packaging or the product itself. For damaged items, defective products, or incorrect orders, we will only accept returns, refunds, or exchanges if notified within 7 days of receipt. Please understand that for products sold through our company, we handle all warranty-related support directly. We do not provide support through other third-party companies or agencies located within Japan.