Rattle from drive when revved in neutral or hard take off in gear.

2tirefire · Jul 15, 2013

After PDS bearing replacement I developed a rattle that sounds like its from the drive or Flywheel housing. At first it was only in neutral when I would give the motor a quick Rev, but now its giving a quick rattle when taking off from a stop. Also developed a vibration when turning left or right when under power, U joints????. Pulling the gearbox now to have a look. When I pulled the drain plug there was a few shavings on magnet. Drive oil came out looking brand new but has only had 10 hours on since change.

Any advise on what to look for would be greatly appreciated.

DP-A, Single bearing Flywheel housing.

First Picture of boat actually in the water.

Don S · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Metal "Shavings" on the magnet is not good. A black goo is normal, but nothing shiny.

2tirefire · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

There was also the black goo. There was 3 little specs that I could see.

Don S · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

2tirefire said:
After PDS bearing replacement I developed a rattle that sounds like its from the drive or Flywheel housing. At first it was only in neutral when I would give the motor a quick Rev, but now its giving a quick rattle when taking off from a stop. Also developed a vibration when turning left or right when under power, U joints????.

It could also be the flex plate bolted to the flywheel (spings coming loose). That's one reason I dislike just pulling the shaft to replace the bearing. If the flex plate is damaged you have no way of inspecting it. If the bearing or bushing in the crankshaft pulls out, it really goes downhill fast.

2tirefire · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Is there a function for these springs, this rattle was not apparent prior to bearing replacement?

Don S · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

The flex plate is also known as a vibration damper. When they get rusty from water getting through the bearing, they tend to fail, come loose and can rattle.
Here is a picture of a typical flex plate/vibration damper.

2tirefire · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Thank you for the picture Don. I'm going to use my inspection camera to see if I can see any damage.

bruceb58 · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

We had a flex plate crack on a 270 drive in a boat we owned. Sounds like identical issue you have.

2tirefire · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Bruce what were your symptoms? Wonder if the vibration I'm feeling is related to the rattle?

bruceb58 · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

2tirefire said:
Bruce what were your symptoms? Wonder if the vibration I'm feeling is related to the rattle?

Felt like bad u-joints. After replacing u-joints, next step was looking at flex plate.

2tirefire · Jul 15, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Exactly what I'm feeling, thanks for your time Don and Bruce. Will update when I find problem.

2tirefire · Jul 17, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

bruceb58 said:
Felt like bad u-joints. After replacing u-joints, next step was looking at flex plate.

After pulling PDS(forgot how much of a pita is was to get the last c clip) I used my inspection camera and all springs are in place and it looks like there is no signs of rust anywhere.

Should I go ahead and replace u joints? If so is a automotive u joint replacement u joint satisfactory?

bruceb58 · Jul 17, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Need to look for cracks in the plate.

2tirefire · Jul 18, 2013

Re: Rattle from drive when revved in neutral or hard take off in gear.

Could not locate any cracks in flexplate. Spent a good hour inspecting with camera. Also having troubles finding U joints that cross over to automotive for my application. Does anybody happen to have that information. It would be greatly appreciated.

Rattle from drive when revved in neutral or hard take off in gear.

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