Rocks in a hubcap (1 Viewer)

[CurtB]

I have a frustrating rattle that sounds like a hubcap full of pebbles. Happens around 2200 RPM, under light load. I can't make it happen unless I'm moving. It happens in all gears, but stops when I push in the clutch. Increasing the load or backing off makes it stop. Happens in two or four wheel drive, hubs locked or not.

It sounds like a loose heat shield...harmonic vibration..I've poked and prodded everything I can get to with no joy. Any ideas? Is there anything inside the bell housing that could come loose?

 

[OSS]

Put the transfer case in neutral then shift through all the gears like you were driving (but car is stopped). Rev slowly up to 2800 rpm then shift to the next gear. Etc.

Still make that noise? Still quiet when pushing in the clutch to shift?

 

[CurtB]

The noise doesn't happen when transfer case is in neutral. But, there is no load either.

 

[OSS]

Are the oil levels correct in the tranny & transfer?

There are heat shields in the engine compartment too and near the steering shaft. They could rattle. Check all those carefully.

 

[micruz60]

I can't make it happen unless I'm moving. It happens in all gears, but stops when I push in the clutch.

Is the sound coming from the firewall / trans area, below the floor?
It stops when you push in the clutch, maybe throwout bearing.
There is a heat shield below drivers seat, over the exhaust, and it could be the cat?

 

[CurtB]

Are the oil levels correct in the tranny & transfer?

There are heat shields in the engine compartment too and near the steering shaft. They could rattle. Check all those carefully.

Oil levels are correct. I've tried all the shields and can't find anything loose.

 

[CurtB]

Is the sound coming from the firewall / trans area, below the floor?
It stops when you push in the clutch, maybe throwout bearing.
There is a heat shield below drivers seat, over the exhaust, and it could be the cat?

Yes. Although it sounds like it is higher in the engine. Doesn't sound like a bearing because it cycles in and out at certain rpm and sounds like thin metal.

 

[OSS]

Try test driving the truck around the block in 4lo without the hubs locked on the street. Be careful. Your max speed in 4th gear in lo range is like 25-30 mph. See if the symptoms are identical at the same RPMs

 

[CurtB]

I'm about to go country on this bitch and climb in the engine compartment while someone drives around