started building my mtx4r yesterday and have a question. I put the rear diff together and was wondering if im suppose to use the small little o rings that go in the bevel gears? I know in mugen offroad cars your not suppose to use them. Another question, the small washers that go behind those small o rings were very hard to slide over the crosspin shafts. Anyways I put the diff together and used the 10,000 fluid it it seems very hard to spin the outdrives, seems like there is 60,000 in the diff instead of 10,000. Any help would be great