This squeaks got me...

Good evening friends,

I searched the forums and didn't find much for this one.
I'm getting a squeaking noise from under the truck while in reverse only. Its a similar sound and intensity as the squeak we get from our leaf springs, but it varies with ground speed. Brakes don't change the noise or pattern. Heres where it makes me scratch my head, no noise when i just roll the truck backwards. Any takers?

Thanks

 

U-joint(s) with dry / rusty bearing cups. Shake 'em to try and feel for any play, and look for signs of rusty dust coming out past the seals.

Failing that, and they're greasable (most prerunners aren't greasable ujoints), grease one at a time until the noise disappears - then change at least that one.

 

Good lookin' trout, sir. You live in a good place for a fly angler.

I should have included that when I'm under the truck and turn the driveshafts by hand, no noise. Maybe the joint will only make noise when its torqued up?
I grease them fairly often but I'll give them another shot this morning. Thanks for the suggestion.

 

It could be the leaf springs when torque shifts them in reverse.