I've just built a diff using xray clear diff orings.
Haven't run the car yet, but they seen better.

I'm using bushings.
I've been playing a lot with the diffs recently, and have come back to the kit red o-rings, 0.3mm shims, and a single 0.1mm 5mm shim behind the o-ring in the case. Seems best compromise between seepage and freeness.

The Xray o-rings sound interesting though... might have to give them a try.

Muchmore blues are also quite good, one question I do have, what shock length is common on the 419? 61.5mm? I'm using the big bore TRF shocks on mine

Yes, 61.5mm top to bottom.

doesn't the car come with big bores?

Yes

right, well in that case I have 2 sets. I ran a BD7 before this so I didn't own the 418. The last tamiya I had was the 417X in 2012.

Good to know

the 419 shocks are slightly different design, but external dimensions are same as 418/417 etc.

bore inside is larger (thinner wall cylinder) and the seals arrangement different.

oh, and a new piston.

My gear diff doesn't connect together well. There is a 1/2 mm gap between diff cases. This is after screwing it together. What do I need to do? It is clearly leaking btw the diff cases.

Did you match up the two sides? There is a locating marker on both and it slides together easily.

If that is ok then check that you assembled the internals correctly and that everything is seated properly before you close the two halves together. There is no way that you should have a gap like that.

On the positive side it's not leaking from outdrives. I am using red orings.

That's not a problem, if the diff is not crunchy. It only means the two halves are kept away by the gasket. If yo want to check just pull out the gasket and reassemble the diff. Any gap left now?

A number of problems might be responsible for the leak here. The screws are not tight enough, the diff halves' mating faces are not flat, the gasket doesn't sit correctly, or it wasn't soaked in oil, etc. Try doing up the screws again. Back them off a bit and re-tighten.

Chris, as mentioned above, the cases only go together one way.

You have to check for the alignment marks on the diff halves, instructions do show where to look but you have to know where to look in the instructions.
It's not printed in super bold type, maybe it should be.

Mark both alignment marks and a mark on the flange of the diff half that is underneath with a silver Sharpie marker. Makes it easy to know when you have the two diff halves matched up to avoid the fitment issues mentioned above. The extra mark on the flange allows me to make sure the mark from the bottom diff half that you can't see is aligned correctly.

I also mark the bearing holders in the bulkhead (the little arrow) with a silver Sharpie to easily be able to know I've got both bearing holders matched up when I'm adjusting the belts.

Good luck to the TRF Team at the ETS in Mattsee Austria.

Hopefully a Tamiya victory