How to build a perfect Tamiya Gear Diff

Building the perfect Tamiya Gear Diff After racing with a gear diff for some time there are some tips and tricks that you can use to buil...

Building the perfect Tamiya Gear Diff

After racing with a gear diff for some time there are some tips and tricks that you can use to build a great Tamiya Gear diff that is smooth, leak free and will last for a very long time between servicing.

Here is what you will need:
  • Tamiya 54428 Steel Bevel Gears ** (although the plastic ones are ok, if you do use plastic ones then just cut off the plastic from the sprue, dont sand them down)
  • Tamiya 42259 Gear Diff 5mm O-ring (red, 8pcs) or Kyosho ORG05 o-rings.
  • TDX AC16003 Smart Shim for Tamiya Gear Diff. 0.3mm (Although the new Tamiya shims are ok as well)
  • Associated Green slime

First up, place a little green slime in both sides where the internal o-Rings go.

then pop in the O-ring.

Pop a little more Green slime on and then fit the shims

I find that I only need one TDX shim on each side when fitting the steel gears. (0.3mm worth of Tamiya Shims if you do not have the TDX shims)

Then pop on the gasket, again I use green slime on this, and then push the gasket on over it. You want to make sure that it reaches the screw holes.

Fit the metal gears. These are fantastic, they are the correct size, no sanding required and they will last a long time before they wear out.

Once you have installed the gears its time to fill the diff with oil, I fill it until the oil floods over the main set of gears. I then let it rest for a while for air to come out and then top it up to this level again if needed.

Now I screw it together, take your time and screw the opposite corners in turn to ensure you dont warp the case. Take care not to screw it too tight at first, once all 4 screws are in and seated in the case then do half turns, again with screws in opposite sides until the screws feel nice and tight.

Here is the final result, a smooth ultra reliable gear diff.

Tip - If making an offroad diff, I would recommend the steel gears. My 501x has had these in for 9 months and they are still fine :)
Tips 6427543092776614629

Post a Comment

  1. Hi
    Where did you get them O-rings and shims in the uk ?

  2. The O-rings can be bought from a lot of places such as JE spares.

    The shims are harder to get (I got mine from RC market in HK) the Tamiya ones are now much better now, and with the steel gears they dont seem to cone. I will add a measurement for the shims later (I need to check them with some digital callipers).



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