Pulled final drive off to check and lube propeller shaft ( drive shaft ) splines while doing a new tire change. I found splines worn @ 42,000 miles ??) and also noticed gear oil will run from pinion joint when differential is tilted down . I didn't find anything in Honda service manual that addressed this but Clymers states; "Check that gear oil has not been leaking from either side of unit (ring gear side or pinion joint side). If there are traces of oil leakage , take the unit to a dealer for oil seal replacement. Has anyone else experienced this ? Is this a dealer only repair ? I found several final drive assemblys on ebay for around $100 but a bit hesitant to buy the same problem I already have ? I can buy all new parts for $150 but not sure about changing the oil seal ? Anyone got ideas ?