Overview
The ARRMA Diff Case (ARA310915) is an essential replacement component for owners of high-performance 1/5 and 1/8 scale ARRMA brushless RC trucks. Whether you're running a KRATON, OUTCAST, TALION, or MOJAVE model, this precision-engineered differential case is designed to withstand the demanding demands of serious RC driving. As a dedicated RC car enthusiast in the UK, you'll appreciate that differential cases are critical components that bear significant stress during aggressive acceleration, cornering, and high-speed runs. This is a genuine ARRMA part manufactured to original specification, ensuring perfect fitment and reliable performance with your existing setup.
Differential cases are among the most heavily loaded components in any RC vehicle's transmission system. When you're pushing your brushless RC truck to its limits—whether bashing in the garden, competing at the track, or exploring off-road terrain—the differential must manage power delivery to both wheels while allowing them to rotate at different speeds during turns. A worn or damaged diff case compromises handling, increases wear on other transmission components, and can lead to mechanical failure at the worst possible moment. The ARRMA Diff Case delivers the durability and precision you need to keep your RC truck performing at its peak, whether you're a weekend basher or serious competitor.
This replacement component is equally valuable whether you're rebuilding a damaged transmission, performing routine maintenance on your ready-to-run RC model, or building up a competition-grade setup. The included gasket ensures a reliable seal that prevents differential fluid leakage, whilst the precision-manufactured design maintains the exact tolerances required for smooth, efficient power delivery. Keep a spare in your toolbox—differential cases are consumable components that may require replacement after sustained high-performance driving.
Key Features
- Tough Composite Construction — The diff case is manufactured from durable composite material that provides excellent strength-to-weight characteristics, delivering long-lasting performance across all driving conditions whilst keeping your RC truck's weight optimised for responsive handling.
- Precision-Manufactured Molded-In Metal Insert — A metal insert is precision-cast directly into the composite body, dramatically increasing durability under extreme loads and preventing the case from stripping or cracking during aggressive acceleration or high-torque situations common with brushless RC trucks.
- Accurately Cut Gasket Included — The gasket is precisely manufactured to fit perfectly with the diff case, ensuring a reliable differential seal that prevents fluid leakage and maintains consistent performance throughout your driving sessions.
- Genuine ARRMA Component — This is an authentic ARRMA original part, not an aftermarket substitute, guaranteeing perfect fitment with your KRATON, OUTCAST, TALION, or MOJAVE RC model and compatibility with all other original ARRMA transmission components.
- Complete Replacement Set — You receive everything needed to complete a differential case replacement: the case itself, gasket, and M5 x 5mm set screw, eliminating the need to source additional hardware.
Technical Performance
The ARRMA Diff Case (ARA310915) is engineered specifically for use in ARRMA's most powerful brushless RC trucks, including the 8S variants of the KRATON and OUTCAST which deliver extraordinary power and torque. The composite material selected for this component offers an ideal balance between weight and strength, critical considerations in high-performance RC vehicle design. The moulded-in metal insert is the engineering highlight—this is not simply a metal pin or bearing; it's a precision-cast element that's integrated into the composite structure during manufacturing, creating a unified component that resists the tremendous shear forces generated by brushless motor torque transmitted through the differential gearing system. Under extreme loads—such as those experienced during rapid acceleration, aggressive cornering at high speed, or terrain impacts—the metal insert prevents the plastic from deforming or stripping, maintaining precise gear engagement and preventing the catastrophic failure that would otherwise compromise your RC truck's transmission. The included gasket is not a generic seal; it's specifically shaped and sized for this diff case, ensuring that differential fluid remains contained and that performance remains consistent across multiple driving sessions. This is a genuine replacement component suitable for owners of 1/5 KRATON 8S models (ARA110002, ARA5208, ARA5808V2T1), 1/5 OUTCAST 8S models (ARA5810, ARA5210, ARA5810V2T1), and compatible with other ARRMA large-scale models. The composite material is resistant to the common solvents and oils used in RC maintenance, ensuring longevity even with regular servicing.
What's in the Box
- 1 x Diff Case (composite with moulded-in metal insert)
- 1 x Diff Gasket
- 1 x M5 x 5mm Set Screw
Frequently Asked Questions
- What ARRMA models is the ARA310915 Diff Case compatible with? — This diff case is a standard component for 1/5 KRATON 8S models including the ARA110002 (4X4 RTR), ARA5208 (EXB Roller), and ARA5808V2T1 (EXB AVC RTR), as well as 1/5 OUTCAST 8S models including the ARA5810 (AVC RTR), ARA5210 (EXB RTR), and ARA5810V2T1 (EXB AVC RTR). Check your model documentation or our compatibility guide to confirm fitment with your specific truck.
- When should I replace my differential case? — You should replace your diff case if you notice grinding or unusual noises from the differential area, if the case shows visible cracks or damage, if your truck pulls to one side indicating uneven power delivery, or if you experience loss of differential fluid. Many serious racers keep a spare diff case on hand for quick maintenance between events or to reduce downtime after damage. Regular inspection during routine maintenance intervals is recommended, especially if you drive aggressively or in sandy conditions.
- Is the composite material durable enough for serious RC driving? — Yes. ARRMA specifies composite diff cases for their flagship brushless trucks including the 8S KRATON and OUTCAST, which are among the most powerful production RC vehicles available. The moulded-in metal insert provides reinforcement at stress points, making this composite case suitable for high-torque brushless motors, extreme acceleration, and aggressive driving. That said, the diff case is a wear component—sustained high-performance use may eventually require replacement, which is normal for RC vehicles at this performance level.
- What is included in this replacement set? — The ARA310915 provides a complete diff case replacement package: the main composite case with integrated metal insert, a precision-cut gasket to ensure a reliable seal, and an M5 x 5mm set screw for fastening. No additional hardware is required to complete installation, though you'll need basic RC tools (hex drivers) and differential fluid for initial filling.
- Can I use an aftermarket diff case instead? — Whilst aftermarket alternatives exist, genuine ARRMA parts are engineered and tested to work perfectly with your truck's transmission system. Authentic ARRMA components guarantee exact fitment and compatibility with your shock absorbers, motor mounts, and other transmission parts. For maximum reliability and performance, we recommend using genuine ARRMA replacement components.
- Is this suitable for beginners? — Differential case replacement is an intermediate-level maintenance task. If you're comfortable performing basic RC maintenance such as cleaning, changing gearbox fluid, or replacing bearings, you'll manage a diff case swap. ARRMA provides detailed instructions with their vehicles, and the modular design makes removal and installation straightforward with standard RC tools. However, if you're new to RC maintenance, consider having an experienced RC enthusiast or hobby shop assist with your first replacement to ensure proper installation and fluid fill levels.
Why Buy from RC Model Shop?
RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the Diff Case today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.
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