Growl at 1600 Engine RPM

[Fochdog]

I just starting hearing a noise in my cruiser while driving home from work.

I would describe the noise as a growling while the tach is around 1600 rpm. I believe I heard it in 3rd and 4th gear, both around 1600 rpm. If I lift the throttle the growling goes away.

I'll try some standard troubleshooting this weekend e.g. pulling the prop shafts one at a time.

Until then does this sound familiar to anyone? Any ideas or thoughts?

Thanks,

 

[cruiserdan]

Is the drivetrain "loaded" or "unloaded" when it happens?

 

[Fochdog]

The growling occurs while I'm just crowding the throttle. Just enough to maintain a steady speed around 40 mph.

 

[cruiserdan]

So basicly a no-load situation?

 

[Fochdog]

Sort of ... If I start to coast with the throttle closed ... no growling. If I tip in just enough to keep going it will start again.

 

[cruiserdan]

My first thought is slip yoke(s) or u-joint(s)

Coast and acceleraton "load" the drive shafts and take up the slack. "No load" gives the shaft a chance to float around a bit.

Try greasing the slip yokes and go for a test drive.

 

[Fochdog]

Thanks ... Good idea! I will add that to my "to do" list for this weekend.