Overview
The Traxxas Sensor-Ready Gear Cover (E-Maxx 3908) TRX3977R is an essential upgrade for E-Maxx owners looking to convert from dual motors to a single brushless motor setup. Designed specifically for the extreme brushless torque and power that the E-Maxx was engineered to handle, this genuine Traxxas spare part allows you to transform your RC car UK into a high-performance single-motor machine with minimal fuss. Whether you're upgrading your existing E-Maxx 3905 or 3903, or building a custom brushless RC monster truck, this gear cover solution provides the clean factory fit and finish that Traxxas is renowned for in the ready to run RC market.
The two-piece gear cover design keeps dirt and debris out of your drivetrain whilst allowing straightforward access to the pinion and spur gear for maintenance and tuning. With a removable dust plug that makes slipper clutch adjustments easy, this is an intelligent engineering solution that understands the needs of serious RC enthusiasts who demand both protection and accessibility. The blue-anodised aluminium motor plate (sold separately as #3997X) works in perfect harmony with this cover to give your brushless installation a professional appearance and robust mechanical reliability.
This is a must-have component if you're serious about maximising the potential of your E-Maxx brushless conversion. RC car enthusiasts across the UK trust Traxxas replacement parts for their quality, durability and exact fitment, and this gear cover is no exception.
Key Features
- Two-Piece Protective Design — The upper and lower gear cover components work together to shield your spur and pinion gears from dirt, dust and debris that would otherwise damage your drivetrain and reduce performance, whilst the modular design still allows quick access when you need to inspect or adjust your gears.
- Removable Dust Plug — The included removable plug makes slipper clutch adjustments straightforward and hassle-free, eliminating the need to disassemble the entire cover just to fine-tune your drivetrain feel and performance characteristics.
- Sensor-Ready Construction — Built specifically to accommodate sensor installations, this gear cover is engineered for modern brushless setups that require telemetry and speed sensing, making it compatible with the latest generation of Traxxas brushless electronics.
- Factory Fit and Finish — Designed as a genuine Traxxas component, this cover integrates seamlessly with the E-Maxx platform to deliver a clean, professional appearance that looks as good as it performs, with no modifications or fabrication required.
- Single Motor Installation Specification — This cover is specifically engineered for single-motor configurations, providing the correct mounting points and clearances for mono brushless setups on E-Maxx models #3905 and #3903.
- Includes Hardware — Three 3x6mm cheese head cap screws are included to secure the cover assembly, ensuring you have everything needed for installation out of the box.
Technical Performance
The Traxxas E-Maxx was engineered from the ground-up to handle extreme brushless torque and power, and this gear cover forms a critical part of that design philosophy. The two-piece construction in durable plastic composite materials provides excellent protection against the harsh conditions that brushless RC monster trucks encounter during aggressive bashing and competition use. The blue-anodised aluminium motor plate (purchased separately) works in partnership with this cover to create a structural system that properly supports the immense forces generated by modern high-KV brushless motors in the 1/10 scale brushless RC category. The removable plug mechanism demonstrates thoughtful engineering, allowing you to access slipper clutch adjustment points without dismantling the entire drivetrain assembly. This is particularly important when running high-torque brushless setups where fine-tuning the clutch engagement characteristics can make the difference between optimal performance and mechanical wear. The sensor-ready design confirms this cover was developed with the latest brushless technology in mind, ensuring compatibility with speed controllers and sensors from Traxxas's current generation of electronics that provide data logging and telemetry functions. The precision fitment ensures no rattling, movement, or vibration that could lead to accelerated wear or noise during operation.
What's in the Box
- Gear cover (upper component) — 1 piece
- Gear cover (lower component) — 1 piece
- Dust plug (removable) — 1 piece
- 3x6mm cheese head cap screws — 3 pieces
What You Need to Complete
- Motor plate #3997X (sold separately) — required for proper single motor installation and alignment
- Brushless motor — required for operation (not included)
- Brushless speed controller/ESC — required for operation (not included)
- Battery (LiPo recommended for brushless E-Maxx) — required for operation (not included)
Frequently Asked Questions
- Is the Traxxas E-Maxx gear cover compatible with my model? — Yes, this sensor-ready gear cover is engineered to fit E-Maxx models #3905 and #3903. It is specifically designed for single motor installations when used with the motor plate #3997X. Always verify your model number before ordering to ensure compatibility.
- Do I need to purchase anything else to install this gear cover? — Yes, you will need the motor plate #3997X (sold separately) to complete the single motor installation properly. This plate provides the correct mounting interface and alignment for your brushless motor. The cover itself includes the fasteners needed for assembly.
- What does sensor-ready mean on this gear cover? — Sensor-ready means the cover is designed to work with Traxxas brushless systems that incorporate speed sensors for telemetry and data logging. The internal geometry and mounting points are optimised for sensor compatibility, allowing you to use advanced electronics that provide real-time performance data and diagnostics.
- Can I use this cover with a dual motor setup? — No, this cover is specifically engineered for single motor installations only. If you have a dual motor E-Maxx, you would need the appropriate dual motor gear cover instead. This single motor version is designed to work with one brushless motor and its associated mounting plate.
- How difficult is it to install this gear cover? — Installation is straightforward for users with basic mechanical knowledge and appropriate tools. The three 3x6mm fasteners secure the cover assembly, and alignment should be intuitive if you're using the correct motor plate #3997X. If you're new to RC car maintenance, consult the official Traxxas manual for your E-Maxx model for detailed step-by-step instructions.
- Will this gear cover reduce access to my drivetrain? — No, the design specifically addresses this concern. The two-piece construction allows relatively easy access to your spur and pinion gears for inspection and adjustment. The removable dust plug gives you quick access to slipper clutch settings without full disassembly.
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 Traxxas Cover, gear (upper & lower) (1pc) / dust plug (1pc) / 3x6mm CS (3 pcs) (for single motor installation, use with motor plate #3997X) TRX3977R 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.
- Brand: Traxxas
- Model Number: TRX3977R
- EAN: 0020334397782
- Product Type: Sensor-Ready Gear Cover (Upper & Lower)
- Spare Part Category: Drivetrain Spares
- Compatibility: E-Maxx models #3905 and #3903
- Installation Type: Single Motor Configuration
- Requires: Motor plate #3997X (sold separately)
- Gear Cover Pieces: 2 (upper and lower)
- Dust Plug: 1 removable piece
- Fasteners Included: 3x 3x6mm cheese head cap screws
- Colour: Standard Traxxas finish
- Material: Durable plastic composite with sensor-ready design
- Features: Protective dirt and debris shield, removable plug for slipper clutch adjustment, clean factory fit and finish
- Purpose: Convert E-Maxx from dual motor to single brushless motor setup
We want to make sure your delivery goes smoothly, so here are some important details about our service:
- For orders above £120, we offer delivery to most mainland UK addresses. For orders under £120, we can still deliver to Northern Ireland and the outlying isles, as long as the item can be sent by Royal Mail, weighs less than 30kg, and fits within 61cm × 46cm × 46cm. Some highland and remote areas may carry an extra delivery charge as couriers often apply surcharges in these locations. If you live in one of these areas, feel free to contact us before ordering so we can confirm the delivery options and costs for you.
- Most of our products include delivery in the price. If your order is under £90, a small delivery fee will apply but do not worry this will always be clearly shown at checkout before you complete your purchase.
- Depending on what you choose at checkout, your order will usually be delivered either the next working day or within 2 working days. For next day delivery please place your order before 2:00pm. Orders are dispatched Monday to Friday only. Some items may take a little longer and if that is the case we will always show the expected delivery time on the product page.
- If your order includes items with different dispatch times we will normally wait and send everything together once all items are in stock. If one of the items is going to take a while we will give you the choice either wait for everything to arrive or let us send the available items now and deliver the rest later. It is up to you.
- We use trusted delivery partners to make sure your order gets to you safely and on time. We use DPD for next working day deliveries and Royal Mail for the 2 day option.
- As soon as your order is on its way we will send you a tracking number by email. If you provide your mobile number at checkout we will also send delivery updates straight to your phone so you can keep an eye on progress.
- If a product is marked as "Dispatched within 3 working days" delivery usually takes around 3 to 5 working days from when your order is placed.
- For customers in Inverness and other parts of the Scottish Highlands deliveries can take up to 2 working days even if you select next day delivery as couriers do not currently offer a guaranteed next day service to those areas.
