laketrout

2016 CCSB 4x4, max tow, tailgate step, 2500 miles.

At 500 miles I replaced the rear shocks with Fox 2.0 and added wheel well liners. Shortly after, I started hearing a rattle/clunk when driving slow speeds over bumps. Double checked to make sure shock bolts were tight, and that the liners weren't hitting anything - all good. After 2000 miles, it has become more noticeable and louder. Thought maybe it was the tailgate or the step, but both seem to be solid.

I need to take it in to Ford, but would like to isolate the rattle/clunk first, otherwise they will (likely) not figure it out. My other concern is that it's the shocks themselves and then I would be charged for diagnostics. If I still had the oem shocks I would swap out for a sanity check, but those pos's went to the scrap heap.

Anyone had something similar? Any ideas on how to pinpoint?

jd50i

get underneath it and bang around
have someone outside the truck as you run over a 2X4 or similar on each wheel.

BShadows

Does it make the sound when you make a tight turn? Like, is body roll causing it to make the clunking sound or only over bumps?

Any difference if there is weight in the bed?

moparado

Defective Fox shock? Wrong shock spec for your truck and bottoming out?
Might want to double check the specs of those new shocks?
Collapsed length, extended length and stroke dimensions if wrong for the vehicle will cause bottoming out of the shock.
Went through all that when i lifted my Jeep Cherokee.

laketrout

Only over bumps and only at slower speeds. If I'm going like 30-40mph I don't hear anything.

I'll test this weekend with some weight in the bed.

I found this thread too, but not sure it's the same issue with the rear leaf springs. May have to try some grease and test:

https://www.f150forum.com/f118/clunk...306127/index4/

thanks everyone.

brnr17

did you ever test this? i'm getting the same rattle from the rear with Liners and fox 2.0's as well.

laketrout

Sorry, did not have time and/or good weather (snow) to test this. Hopefully within the next week.

rts9364

Has anything happened on this? I am in a very similar situation, other than I just installed Icon 2.0 shocks and no wheel liners (yet). Also around 500 miles (now I have 1100 miles).
Based on what you describe, I am hearing the same rattle/clunk. It sounds almost like the bed or tailgate is loose. I do have LineX, so one thought is the bed bolts are not tight; I will check that. Like the OP, I checked my shocks last night and all is still tight. Really annoying...

rts9364

^^^
I should add to the above: I still have my factory shocks on a shelf, so I could somewhat easily reinstall those and see what happens. It's hard to believe it is anything related to the shock, other than the timing of it all, though I will say I don't recall the noise starting until some while after the change. (Initially after install I recall going over a bump at ~20 mph and being impressed how quiet and controlled the rear was.)

rddakota

let us know if going back to stock eliminates the rattle. I believe I have the same issue, sounds like it coming for the back seat but I checked all possible places, all seems to be "tied" down.