HBW150V - Noise! What does it mean?

[Linda - Olympia]

We're hearing a gradually increasing rhythmical noise when the engine is in neutral. No noise forward, no noise reverse. Noise begins after engine has warmed 5-15 seconds in neutral. Not vibration. Better described as a repetitive clanking.

One opinion is that the throw-out bearing (operating cone) may be worn.

Any other ideas?

[a64pilot]

Take a big, long screwdriver, use it like a stethoscope and see if you can determine source, can buy a mechanics stethoscope too for not much, ought to at least rule out the engine as the noise source.
Type of engine / transmission? Common for an automobile to have a cracked torque convertor flex plate to make this noise, even a loose flywheel is possible? Maybe even engine mount?


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[LeaseOnLife]

How is the transmission coupled to the engine / what engine ?

It could be the driveplate/torsion damper is worn out, typically the springs loose tension, then there is play and it rattles, specifically when not loaded.

Dirk

[FSMike]

Originally Posted by Linda - Olympia

We're hearing a gradually increasing rhythmical noise when the engine is in neutral. ----

Increasing as in loudness, or as in frequency of occurrence?
Is the rpm staying the same?

[Linda - Olympia]

Thanks. Hmm. Engine is Universal 5432 (32 hp) with HBW150V (Hurth V drive transmission). Noise occurrs in neutral, low rpm. Increases in loudness, not frequency, as engine warms up. In gear, forward or reverse, noise goes away as rpm increases.

Per one mechanic, who listened to sound in neutral, forward & reverse, could be the throw-out bearing (also called an operating cone). He's researching and we're researching.

[LeaseOnLife]

What cone? The HBW150V uses clutch packs to switch to forward or reverse. There are a bunch of bearings, but they typically make more noise (when bad) at higher load and higher speed.

The term "throw out bearing" is used for manual transmissions with clutch in cars and trucks, different animal. Maybe something lost in translation??