had problems with vibration when travelling any speed.Changed the doughnut and had a wheel bearing on its way out so changed that but still had vibration and was gettting worse found the problem i think the front prop had sideways play took of the prop found the nut loose on the flange from the out-put transferbox tightened it but seal may have gone.oil drip still after tightened nut so . How easy is it to change the oil seal on the output shaft front . looks like i can get to all the bolts on the casing or am i opening a can of worms. any help?