ZF Hurth 450

[Mike]

My transmission has a louder whine in reverse than my previous Borg Warner transmissions, is this a characteristic of the transmission? Also the boat is a 2000 Skier with 282 hours and I do not think the fluid has ever been changed what is recommended interval for trans. fluid?

[RonT]

Your ZF is slightly louder in reverse than the B/W, I contribute this to the aluminum case vs cast iron case for the B/W, but it should sound smooth not clunking, that would be an indicator that the vibration dampner is going out.  I reccomend changing the trans oil annually or every 100 hrs, I have a few customers who only put 20-30 hrs a year on their boat & i check their oil annually & change it every other year. The trans oil service is also the same as shaft alignment time.   (Dextron III)