2006-2012 Honda TRX90 TRX90EX/X Service Manual, Page 184Get this manual
CRANKCASETRANSMISSIONCRANKSHAFT ASSEMBLY TRANSMISSION
Clean all parts in solventApply clean engine oil to mainshaftcountershaft and each gear teethAssemble all parts into their original positions Check the gears for freedom of movement or rotation on the shaft Do not reuse worn snap ring which could easily spin in the groove Check that the snap rings are seated in the grooves and align their end gaps with the grooves of the splineSNAP RING CORRECT INCORRECT