HR Steel Helical Diff Ring/Pinion for ARRMA BLX 3S & 4S

Regular price $49.99

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This is the Hot Racing steel helical differential ring pinion for the Arrma BLX 3S/4S 1/10th scale 4WD vehicles.


  • Precision-machined helical spiral-cut gears offer inherently greater strength and smooth operation than the factory bevel gears.
  • High-carbon steel construction
  • Stronger than the stock bevel plastic gears
  • Maintains the stock 37T/13T ratio


  • Material: Steel
  • Weight: 2.35oz (66.75g)



  1. Remove Slipper Nut.
  2. Set desired slipper tension.
  3. Remove transmission.
  4. Apply a few drops of blue thread-locker down the rear slipper hub opening onto the slipper tension screw.
  5. Allow 24hrs to cure.
  6. Reinstall transmission.



(1) 37T Diff Spiral Cut Ring Gear
(1) 13T Spiral Cut Pinion Gear

  • Requires removal of slipper nut. See the instructions above. 
  • It is recommended to use a Medium (blue) thread-locking compound if screws are threaded into metal
  • High temp grease is recommended for the Diff Gear with Silicone Diff Fluid for Gear Diffs inside.
  • Replaces bevel-Plastic gears AR310873. AR310872.
  • Use with ARAC4023 Composite Diff case Cover or ATF11A01 Aluminum Diff case Cover.
  • If using ARAC4023 you will only use the diff cover plate. You do not need to use the back plate.



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