Hurth Trans noise

[daddy d]

1989 390 express 800 hours, 454 gas with hurth trans, added (stabil) to fuel system, ran under power for one hour noticed both trans started making a rumble noise at lower rpm, more so on the starbord side ????? cutlass bearings are tight, anyone know what could cause this, noise sems to quit at higher rpm, trans fluid is clean, could this be a torshional vibration issue??

Thanks Daddy D

 

[northern]

We have same transmission and engines. Boat has 1750 hours Port transmission has alway had a sound at idle but under power it goes away. Change ATF once a year always clean and no burnt smell.

 

[sbw1]

Make sure your idle rpm is set at factory spec and see if it goes away.

 

[Jeepers]

same boat, same noise. after reading through many posts the general concensus seems to be 1) make sure motor has a good tuneup 2)change out tranny ATF to tractor 25 hydraulic fluid. Both are on my to-do list.