Some of the new gears available can be a snug fit.............I had one recently that the diameter of the dogs were near the same size in OD as the ID of the mating gear, and this was 1st gear too. I ground a bit off the OD of the sliding gear and all was well.............If I'd assembled it as it was, first would have been a right bitch to engage and perhaps stick when changing to 2nd. When compared to an original gear the diameter of the dog engagement was a lot smaller this on the G 10 gear causing the binding of the dogs on G 9. Again this being first gear..............