ARRMA GP4 29mm Front Rear RC Differential Set 80K Oil ARA311199

The ARRMA ARA311199 is a genuine factory-assembled front or rear differential for compatible ARRMA 6S RC trucks, including the 1/7 Big Rock 6S and 1/8 Kraton 6S EXB. Featuring a 43-tooth GP4 spiral-cut steel main gear, 29mm open differential construction and pre-filled 80,000 cSt silicone oil, it provides a convenient replacement for worn or damaged drivetrain components.

Features

• Genuine ARRMA Replacement: Designed for compatible ARRMA 6S vehicles requiring the GP4 29mm front or rear differential assembly.
• Front or Rear Installation: One differential assembly can be fitted in either supported axle position, depending on the vehicle's factory specification.
• Factory Assembled: Supplied as a pre-built differential to reduce the time required for drivetrain servicing.
• Pre-Filled with 80K Oil: Contains 80,000 cSt silicone differential oil for consistent factory-specified differential action.
• 43T GP4 Spiral-Cut Main Gear: Steel main gear is designed to withstand the loads generated by powerful 6S brushless drivetrains.
• Steel Internal Gears: Durable internal gears transfer power between the differential outputs during acceleration and cornering.
• 29mm Open Differential: Conventional open differential design allows left and right wheels to rotate at different speeds.
• Reinforced Composite Case: Composite differential housing with an integrated steel insert provides structural strength.
• Metal Cross Shafts: Support the internal differential gear assembly under drivetrain loads.
• Rubber-Shielded Bearings: Included bearings support smooth rotation and simplify replacement of the original assembly.
• 5mm GP4 Configuration: Matches compatible ARRMA GP4 drivetrain components using the specified 5mm configuration.
• Serviceable Drivetrain Component: Differential oil can be changed as part of routine maintenance to suit the vehicle's setup requirements.

Specifications

• Brand: ARRMA
• Manufacturer Part Number: ARA311199
• SKU: ARA311199
• Product Type: Complete Front or Rear RC Differential Assembly
• Differential Design: Open Gear Differential
• Differential Case Size: 29mm
• Gear System: GP4 Spiral Cut
• Main Gear Material: Steel
• Main Gear Tooth Count: 43T
• Internal Gears: Steel
• Housing Material: Composite with Integrated Steel Insert
• Cross Shafts: Metal
• Bearings: Rubber-Shielded
• Output Configuration: GP4 5mm
• Factory Differential Oil: 80,000 cSt Silicone Oil
• Installation Position: Front or Rear
• Assembly: Factory Assembled and Oil-Filled
• Quantity: 1 Differential Assembly
• Confirmed Compatible Vehicle: ARRMA Big Rock 6S 4WD 1/7 (ARA7612)
• Confirmed Compatible Vehicle: ARRMA Kraton 6S EXB 4WD 1/8 (ARA8708T1)
• Additional Manufacturer-Listed Fitment: Selected Kraton 6S V6, Kraton 6S EXB V6, Talion 6S EXB V6 and Notorious 6S V6 Models
• Application: Replacement Differential for Compatible ARRMA 6S Drivetrains

Includes

• 1 x ARRMA GP4 29mm Front or Rear Open Differential Assembly with 43T Spiral-Cut Steel Main Gear
• 80,000 cSt Silicone Differential Oil (Factory-Filled)
• Rubber-Shielded Differential Bearings (Installed)

FAQ

Does ARRMA ARA311199 fit the front and rear of a Big Rock 6S? Yes. ARRMA lists ARA311199 for the 1/7 Big Rock 6S 4WD, and the differential is designed for installation in compatible front or rear positions. One package contains one differential, not a pair.

Will this differential fit the ARRMA Kraton 6S EXB ARA8708T1? Yes. The ARRMA Kraton 6S EXB ARA8708T1 is included in the manufacturer's fitment list. OZRC recommends confirming the exact vehicle version and differential part number before ordering.

Is the differential already assembled and filled with oil? Yes. ARRMA supplies this differential factory-assembled and pre-filled with 80,000 cSt silicone oil. It is intended to simplify drivetrain replacement without building the internal differential from individual components.

Does the set include the complete front and rear drivetrain gearbox? No. ARA311199 contains one differential assembly with its main gear, internal components and bearings. The surrounding gearbox housing, mating input gear and other vehicle-specific drivetrain parts are not listed as included.

Important Notes

• This package contains one differential that can be used in a compatible front or rear position. It does not contain two differentials.
• Verify the exact vehicle model and version against ARRMA's parts diagram before ordering. Not all ARRMA 6S vehicles use the same differential assembly.
• The differential is factory-filled with 80,000 cSt silicone oil. Changing the oil viscosity will alter the handling and differential action.
• Check the mating input gear, bearings and surrounding gearbox components for damage before installing the replacement differential.
• Confirm correct gear engagement and free rotation after reassembly.
• Gearbox housing, input pinion, differential mounting hardware, tools and the complete RC vehicle are not included unless separately specified.
• Some retailers list additional differential shims in their package description, but ARRMA's standard manufacturer contents specify one assembled differential only. Check the physical package before relying on extra shims being supplied.