A little while back, the truck started making a little noise when
backing up - like a cricket, just a couple of peeps, then nothing.
Then, I started noticing the noise occasionally, but only when the truck
window was open. Now I can hear it with the window is closed - it
sounds very much like crickets, and is coming from the rearend
somewheres, I think. It's not in the suspension or similar, since it
doesn't react to road bumps. It doesn't seem to be varying according to
speed, but that's a bit hard to tell 'cause it's buried by road/engine
noise fairly quickly as I speed up.
Truck behaves fine, but the crickets are really annoying me. Sounds
like something needs to be greased or sommat, but what?