Heavy Clunk from Rear

So here's the story: When flexing the truck at low speeds (or high speed over a wash-board dirt road) I hear a very solid sounding clunk or thump coming from the rear. Today I was able to narrow it down to the passenger rear; basically I had my wife drive in and out of our driveway at ~5-10MPH and when the truck dips while turning I was able to locate the noise while hanging onto the sliders and/or walking along side the truck. Seems to be coming from the passenger rear leafs as they are compressed and decompressed.

I have been searching the archives for the past week and still haven't found a cause or solution to this noise. I checked the torque on the u-bolts, shocks, spare tire holder (even removed the spare tire), lug nuts, the rear bumper, and greased all of the zerks.

The rear leafs are OME Dakars, with OME AAL (D6XL), Nitrocharger Sport shocks, and Elite rear bumper. The bed is empty of weight. I know that the noise isn't axle wrap (use to have it pretty bad) and I can't think of anything else it could be. The body mounts and bed bolts looked snug but tomorrow I will check the torque. The passenger leafs do show a bit of daylight between a few of the springs while the drivers side does not. Hmm, maybe that would be causing the noise?

Any ideas and opinions would be helpful at this point. It sounds pretty bad the more that the truck flexes and just want to ensure that this noise isn't a more serious issue than just noise.

 

I had the same thing with 2 sets of the same leafs you have. Both sets went full negative arch and both got replaced for free on warranty. I'm not sure exactly what causes that "thunk" but on this third set of leafs, I mounted a set of 4.5" energy suspension bumpstops (cheap, $55 on Amazon) on the frame instead of on top of the leaf pack. No more "thunk" at full droop or full stuff. The bumps are soft enough that I don't even feel it when they get compressed by the leafs. The advantages of frame mounted bumps over leaf mounted are that if they get destroyed or torn off, I can replace them without messing with the leaf pack, and that leaf mounted bumps often miss the frame at full stuff, since they angle inward when the axle moves up. Frame mounted stays at the same angle regardless of axle movement.

 

Geez, how long did it take for them to negative arch? Mine still look and react normal. My thump/clunk isn't from bottoming out.

 

Is it the shock fully extending? You must be at least 3.5" in the rear with the D6XL. Maybe you don't have enough travel in the Nitrocharger's? If you're rear leaf is extending rapidly and it fully extends the shock, you will definitely here a clunk...

 

Hmm i didn't think of that. And it does do it more pronouced when it is a sudden terrain shift rather than a 2 mph gradual flex. thanks for the idea. i'll go out there and check into it.

 

I wouldn't be surprised if that was it. Try rocking the truck side to side and see if you hear it. Push above the rear wheel well. Also Try jacking it up from the frame and watch to see as your shock extends the travel you get.

 

I wouldn't be surprised if that was it. Try rocking the truck side to side and see if you hear it. Push above the rear wheel well. Also Try jacking it up from the frame and watch to see as your shock extends the travel you get.

 

I wasn't able to get out and jack the rear of the truck frame up today, but I did roll around under there and check the torque on all of the body mounts. I found one bolt completely missing that holds the bed to the frame, and then also found another bolt barely hanging on that also mounts the bed to the frame. I'm going to get that fixed (once I find the right bolt) and see if that fixes it. Tomorrow if it is warmer and less windy I will lift the truck up by the frame and see how much the rear axle will droop.

 

that might have something to do with it...

 

I had to go to extended 5125s due to having a clunk the 5100s wernt long enough for me with my dakars and 1.5" shakle