GPM Racing Aluminium Outer Portal Drive Housing (Front or Rear)-18pcs Set for Traxxas 1/10 TRX4 (TRX4021A)
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.
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★★★★★
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
- 1/10
- Weight
- 20 g
About this product
Precision 6061-T6 Outer Portal Housing for TRX4
The TRX4021A aftermarket outer portal drive housing set is supplied as 18 pieces for fitment to TRX4 Trail Crawler knuckle assemblies, intended for either front or rear installation. Machined from 6061-T6 aluminium, these housings are designed to replace the plastic outer shells and provide an improved mounting surface to help maintain inner gear alignment under load.
Screws supplied are stainless steel cap head items for assembly, and the housings are dimensioned for straightforward replacement with original plastic neighbours so most installs are plug-and-play. The components use a 3D-machined, low-profile design with precision edges to maintain correct mesh and running clearance in portal gear stacks.
Operationally the parts stabilise the inner gears within the portal housing to reduce flex that can affect gear engagement and steering precision on technical trails. They are compatible with front or rear portals and list a midpoint measurement of 93mm between damper and tie rod as a reference for siting on standard TRX4 knuckle configurations.
This item is compatible with
- TRAXXAS TRX4 Defender Trail Crawler
Which axles can these housings be fitted to?
This 18pcs set is specified to supply the outer portal housings for either the front or rear axle on TRX4 knuckle layouts.
What fasteners are included and how many?
The kit includes stainless steel cap head screws to mount the housings; these fasteners are provided to ensure secure assembly with the aluminium shells.
Will the aluminium housings maintain gear mesh with stock parts?
The housings are precision-machined to preserve gear mesh and clearance when installed with original adjacent components, helping to reduce unwanted play and maintain consistent engagement. Write Product Review Please sign in your account before you can write any review.
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
