Parts/Drivetrain/Differentials & diff parts/Samix Brass Differential Case for Traxxas TRX-4 (Gold) (17g)
Samix Brass Differential Case for Traxxas TRX-4 (Gold) (17g)
Samix

Samix Brass Differential Case for Traxxas TRX-4 (Gold) (17g)

Part # SAMTRX4-40662.3(3)
Where to buy
$32.99
AMain Hobbies
Seen Oct 12, 2026
$32.99Buy
Prices are as last seen at the store; stock is not tracked.

About this part

The Samix Traxxas TRX-4 Brass Differential Case is a direct fit upgrade for the stock plastic TRX-4 diff cup. This machined brass upgrade is stronger than the stock parts and will help to create a longer lasting differential. Plus the cup weighs 17 grams, so it helps to add weight down low and lower the overall center of gravity. Package includes one brass diff cup. 
CA Residents Prop 65 Warning WARNING: This product can expose you to chemicals including Di(2-ethylhexyl)phthalate (DEHP), which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov Details...

Reviews2.3 · 3 reviews

Jon WoodardVerified owneron Samix Brass Differential Case for Traxxas TRX-4 (Gold) (17g)

Upon receiving this part I began to fit it only to realise that it has been machined wrong and the diff locking spool does not fit into the teeth in the samix diff case yet I have x3 hot racing ones and x4 yeah racing ones and it fits on all those perfectly plus the standard traxxas diff case ??

1 found this helpful
Alec Tinsleyon Samix Brass Differential Case for Traxxas TRX-4 (Gold) (17g)

Had no issue with the teeth meshing correctly. The machine work appeared to be quality. There were no burrs and all surfaces were finished smoothly. Quality part for the front or rear diff.

Rrr JjjVerified ownerMay 12, 2022on Samix Brass Differential Case for Traxxas TRX-4 (Gold) (17g)

Does not fit with stock trx4 parts. The mesh is too small. Tried 2 of them.

1 found this helpful
What reviewers say

Reviewers disagree sharply on fit. Two verified-owner reviews report poor fit: one says the gear mesh is too small and the part did not fit stock TRX-4 parts after trying two units; the other says the locking spool does not engage the teeth in the Samix case, while the same spool fits other aftermarket cases and the stock Traxxas case. A third reviewer reports correct tooth meshing, smooth finishing and no burrs, calling it good quality for front or rear use. The reviews do not clearly establish whether the problem is isolated to particular batches. Reviews are few and conflicting.

  • + Smooth surface finish
  • + No burrs reported
  • + Good machine work quality
  • − Gear mesh reported too small
  • − Locking spool does not engage teeth
  • − Does not fit stock TRX-4 parts for some buyers
Summary generated from the reviews above.

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