Strange knocking/rattling noise in rear

[galeo7171]

When I let off the gas I hear a loud knocking noise coming from the rear of the 1009. I did notice that my right rear tire has no wheel weight, so maybe its causing enough vibration to rattle something?? What could cause a loud noise in the rear end when you let off gas? It seems to happen only at certain speeds too

 

[HeadWizard]

Wheel weight wont make much difference on that large a tire.

Is it a noise ONLY when you let off the pedal, as in ONE clunk, or does it make more than one noise - as in continuous noise. If it's a one clunk thing, its either a u-joint or excessive ply int the rear 3rd member.

 

[galeo7171]

It's a continuous noise. It happens around 45 mph.

 

[maritimer]

u joint souinds like, mine did that till i replaced them and viola noise gone

 

[AJMBLAZER]

I was just thinking U joint too. Try shifting into N at that speed. The sound should go away.

 

[HAWKMAN]

u joint souinds like, mine did that till i replaced them and viola noise gone

I agree, put truck in neutral and grap driveshaft and try to twist you'll see the bad joint.

 

[Braunchitis]

u joint souinds like, mine did that till i replaced them and viola noise gone

Mine was making a viola noise too. So, I tuned the U-joints down and converted it into a more pleasing cello noise.

Now my truck sounds like this:

http://www.youtube.com/watch?v=vdwgz98d_6I&feature=related