Arctic Cat 400 Auto Snorkels?

Good morning, I am new to the forum. I'm 75 years old and love getting ATVs back to usable condition. I particularly like the 2006-2009 Arctic Cat 250 Utility. I currently own 6. The 2006 I am working on only has reverse and low gear. The "drive shaft" in the transmission is completely stripped where the high gear would mesh. Has anyone on here replaced the shaft. I'm told I have to split the case. I was hoping that someone on here could let me know how hard it will be. I already have it stripped down to where the shaft coming in from the clutch side is the only thing left. I was hoping I could just remove the driven clutch and drive it out from there. Directions say different. Any help would be greatly appreciated.

Здравствуйте, нужна помощь по ремонту багги Arctic Cat 700 EFI, пропала искра, датчик коленвала импульс есть, Самодиагностика показывает две ошибки AC99,AC96. все провода проверил на целостность, все датчики блоком определяются, не включается топливный насос. Провода от ECU до реле насоса и от реле до насоса исправны. Поставил подменный ECU, ничего не изменилось.   

What oil does everyone like to run in the older quads? 

Will the top end of a 400 fit a 366 the price is so much cheaper
 

I bought a 2008 arctic at 366 with 120hrs. When i red line it in neutral is smokes blue a lot. When I put it in high range it has problems getting over 35km/h. I bought it and had to clean the carb. It ran ok after i cleaned it. Not I have this problem.