The last few days I notice a kind of clicking/metal on metal sound coming from what sounds like the front of the truck. Here's what I can tell about it so far:
- It is speed dependent - it only makes noise from about 20-30mph; above or beyond that, nothing. And you can definitely tell it's coming from something that's rotating because you can hear rotation in the noise.
- It is load dependent - only makes noise under acceleration AND under load, ie going up a hill. Nothing at all going downhill, almost never on flat ground.
- It is not gear dependent - it makes it in 1-4 and OD, gated specifically into each gear.
- It is not constant. It will do it for a couple of seconds, then go away. Or sometimes for 7/8 seconds and then go away.
- It doesn't seem to care if the wheels are straight or turned in either direction.
I'm at a bit of a loss. I'm kind of thinking wheel bearing or CV joint, but I've had both go bad on different vehicles before - bearings have always just gotten progressively louder and worse at speed, CV joints usually show up mostly on turning in a certain direction. I don't really feel the telltale clunk of a U-joint, and at any rate it's more of a clackety/grindy metal sound.
What do you guys think? I won't have time until this weekend to put this up in the air to take a better look..