Originally posted by BigDogRacing
WC- most tranny cases don't require you "push" or force the diff bearings into them. This would probably account for why you haven't chipped any teeth- yours is shimmed without needing any shims! Since I began studying the problem a few weeks ago, I have noticed some tranny cases like yours and there are a number of people who say the same thing you do- no problems. However, I'm friends with a Tamiya sponsored driver and the sponsored guys are getting the oneway diff rings by the box fulls, so I don't think there's any questions of whether or not there's an actual problem.
heehee... I have 5 gearcases spread between 2 cars.
(And scored a scarily HUGE supply of new diff gears too.)
There's been sites that recommend sanding out the nubs... but
no, if you look real close I think that's Tamiya's deliberate design.
(imho They just forgot to instruct users to PUSH the diff in!?)
As long as you push it in, the gearbox cap's 3 screws (I changed
to machine hexheads) are strong enough to hold it in even after
a hard knock. But they're not strong enough to push it in for you,
usually leads to stripped threads before the cover is snug tight.
I have even tried using the gearcase cover to push... but that
doesn't work as well as pushing on the diff itself before putting
the cover on.
Its an easy visual check whether the diff is sitting on the nubs...
just look at the outdrive, there should be same amt of bearing
visible all around it. If the aperture is oval/elongated, then the
gearcase cover is ajar and the diff is not sitting correctly.