First post on the forum. Enjoying your build. Mine is almost complete. (2 weekends worth) I found a pain also. The gear boxes, same problem as you. Gears are not marked well and I found myself re-doing them often! They are very wearing, your not the only one. The instructions for Tamiya are not as good as usual, I think they rushed this out. Many mistakes will be made as not written as clear as they should be.

For doing the tracks I mounted the drive sprockets first, loosened the idler wheel (adjustment wheel), then put tracks on and adjusted them equally. May be easier?

I found the build frustrating at times, some Tamiya, and some my dumb fault.

One more thing, I did not test mine as I should have, worn out from all the bits and pieces. I hope the lights were marked right as the wiring seem to be too long on one side (front and back) and very short after routing per instructions. I could not plug in into DMD with top body on it's side, so will see?

Any way keep the builds coming, I'm enjoying them.