Zach Tarbell

Howdy-

I have a 2010 XLT 4x4 crew cab, 5.4l, leveled on 33's. When driving over speed bumps, pot holes, rough dirt farm roads or washboard roads, my truck makes a crazy rattle from the rear end of the truck. I've so far been unable to find anything online that would provide a source of the noise or solution. It sounds like the shocks are about to fire themselves through the bed and the rear axle depart the vehicle! I can best describe it as a morse-code type metal-on-metal rattle, which seems to be directly related to axle movement.

For the life of me I cannot find where or what it is coming from. My truck has 190k on it, and some rust (rockers) but is tight and pretty darn clean for it's age.
The noise cannot be replicated by shaking the truck, bouncing on the rear bumper, shaking the bed side to side. I have only been able to replicate the noise while driving over rough surfaces that cycle the rear suspension. The noise has nothing to do with going into gear, forward or reverse, nor anything to do with throttle input.

Based on searching threads here about mystery rattles, I have already:

Removed the trailer ball hitch, No change.
Removed the tailgate, No change.
Re-torqued rear shock bolts, No change.
Removed shocks (Bilstein 5100) all together, Made the rattle worse!
Edit: Removed spare tire, No change.
Tightened rear axle u-bolts. No change.
Removed the rear body mount dampeners, No change.
Cleaned and lubed the leaf spring pads with silicone, polyurethane bushing grease. No change.
Sprayed the leaf spring bushings with penetrating oil. No damn change!

My rear brakes are tight, driveshaft u-joints are tight. The truck drives normally, no vibrations, the noise has nothing to do with turning.
I cannot find anything like heat shields, or exhaust pipe that's hitting something, nor anywhere have I found shining metal or rust dust that would suggest something broken/loose/rubbing.

I have yet to pull the rear axle u-bolts and inspect the center section of the leaf springs, but I am hesitant to do this if it leads to another dead end!

Can anybody lead me to a solution??? I'm pulling my hair out over this, help!!

GeekMan

You have a spare tire under the bed? Is it secured?

Zach Tarbell

Oop, forgot to mention that! Similar to my shocks, I both re-tightened, and then altogether removed my spare. No change....!

OD52

Check on "top" of the frame on the drivers side behind the rear tire just before the rear bumper area, you might find a cast iron weight (around 17lbs.) mounted there on rubber dampers with 2 bolts that could have come loose or the rubber dampers have failed causing it to flop around when hitting bumps. My truck had one... I removed it before it caused any problems. I guess it is some sort of vibration damper.

Brokemillwright

I wish mine had the damper, my bed bounces and it bugs me. I've chased a noise similar to that, all 3 times have been shock related, with the bolts tightened down I could slide the shock sideways- crap bushings. Is your e-brake line on driver side secure? There is a little clip that came undone and I always thought could be a culprit for mine

OD52

It didn't make any difference on my truck, vibration was the same with or without the damper, what did help was adding some weight to the rear/bed of the truck by installing a bed-rug, a heavy rubber bed mat, a bed extender and a tonneau cover (approx. 125lbs).

Zach Tarbell

Looked between rear bumper and rear wheel on top of the frame. Both sides, nothing. No kind of weight to be seen.

I am now leaning towards something leaf spring related. Despite spraying penetrating fluid on the bushings and finding no difference, I am wondering if I have a broken bolt or sleeve in one of more of the six bushings.

I am still going crazy at how bad this sounds and yet cannot find an obvious cause.....