GPM Racing Aluminium 7075-T6 Front and Rear Upper Bulkhead+Medium Carbon Steel 32/10T Front and Rear Differential Gear Set for Traxxas 1/6 4WD XRT 8S-78086-4 (XRT12131032)
We are the importer of record — the price you see is the price you pay.
Handled by us in the UK under the Consumer Rights Act — no sending it overseas.
What our customers say
A selection of recent five-star reviews, as written.
-
★★★★★
Ordered flishrc cobra. Communication was great. Ordered larger batteries but they were the wrong size. Olly shipped the right batteries and gave a refund for the difference I paid. Couldn't ask for more. Thanks for the help with the order.
Robert, 22 September 2026
-
★★★★★
Very helpful when the vehicle I wanted wasn't in stock. Very fast deliver too.
Anna Abbott, 17 September 2026
-
★★★★★
Excellent service speedy delivery and good customer service
GLYN, 10 September 2026
-
★★★★★
Great product and service. I enjoy buying from these guys. Thanks to radio-controllled.co.uk.
Paul Jordan, 3 September 2026
-
★★★★★
Dealt with customer services over an order I accidently placed, they were prompt and dealt with it will, completely refunded within a small window of time, thanks!
Oliver Galustian, 23 July 2026
-
★★★★★
Really good online rc store with some great products and sales on. The owner is very knowledgeable as well.
Simon, 19 July 2026
-
★★★★★
Product delivered promptly and in excellent condition 👍had very helpful and prompt responses from Olly to all my questions, I will definitely be using them again 👍
Mark Clucas, 30 January 2026
-
★★★★★
The customer service and advice were first class!
Steve Avery, 9 September 2025
-
★★★★★
The seller knew I was after one and very kindly informed me when they came back into stock so now have a Flywing Bell 206. Fantastic bit of kit. Well worth the wait.
Pete Goddard, 15 April 2025
-
★★★★★
Great service, car arrived fast and really well packaged. Also, I had a little problem....(which turned out to be me doing it wrong) but someone replied the same evening! Will definitely be buying from them again.
Graham Rousseau, 10 February 2025
Key Specs
- Scale
- 1/6
- Weight
- 430 g
About this product
Precision aluminium bulkheads and medium carbon steel diff gears
This GPM upgrade pairs precision aluminium front and rear upper bulkheads with a medium carbon steel differential bevel gear set for the Traxxas X-MAXX 8S. The combination focuses on stronger upper chassis support and improved resistance to differential tooth wear, helping maintain a stable gear mesh under high torque conditions.
Packing includes
- Rear upper bulkhead – 1pc
- Front upper bulkhead – 1pc
- Grade 12.9 black cap head screws 4×16 – 2pcs
- Grade 12.9 black cap head screws 4×18 – 2pcs
- Diff bevel gear 32T – 2pcs
- Front pinion gear 10T – 1pc
- Rear pinion gear 10T – 1pc
- Bearing 15x24x5 – 2pcs
Original Name / Part No:
- 7720?7727?7727X+7790+7791+7792
Compatible Models
- TRAXXAS-1/5 ELECTRIC 4WD X-MAXX 8S MONSTER TRUCK
- TRAXXAS-1/6 4WD XRT 8S-78086-4
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Made to order: GPM Racing parts are shipped to us from GPM’s factory, so please allow around 14 days for dispatch.
What our customers say
A selection of recent five-star reviews, as written.
-
★★★★★
Ordered flishrc cobra. Communication was great. Ordered larger batteries but they were the wrong size. Olly shipped the right batteries and gave a refund for the difference I paid. Couldn't ask for more. Thanks for the help with the order.
Robert, 22 September 2026
-
★★★★★
Very helpful when the vehicle I wanted wasn't in stock. Very fast deliver too.
Anna Abbott, 17 September 2026
-
★★★★★
Excellent service speedy delivery and good customer service
GLYN, 10 September 2026
-
★★★★★
Great product and service. I enjoy buying from these guys. Thanks to radio-controllled.co.uk.
Paul Jordan, 3 September 2026
-
★★★★★
Dealt with customer services over an order I accidently placed, they were prompt and dealt with it will, completely refunded within a small window of time, thanks!
Oliver Galustian, 23 July 2026
-
★★★★★
Really good online rc store with some great products and sales on. The owner is very knowledgeable as well.
Simon, 19 July 2026
-
★★★★★
Product delivered promptly and in excellent condition 👍had very helpful and prompt responses from Olly to all my questions, I will definitely be using them again 👍
Mark Clucas, 30 January 2026
-
★★★★★
The customer service and advice were first class!
Steve Avery, 9 September 2025
-
★★★★★
The seller knew I was after one and very kindly informed me when they came back into stock so now have a Flywing Bell 206. Fantastic bit of kit. Well worth the wait.
Pete Goddard, 15 April 2025
-
★★★★★
Great service, car arrived fast and really well packaged. Also, I had a little problem....(which turned out to be me doing it wrong) but someone replied the same evening! Will definitely be buying from them again.
Graham Rousseau, 10 February 2025
