Riddle me this: Rear end clunk/rattle...none of the usual suspects

Hello all,

I haven't posted much...I enjoy the search function and am usually able to answer my questions that way! But I have searched and searched and tried everything I know to try and can't figure this out...hoping someone here can help me.

So here is the problem: 2007 TRD Sport DCLB with 75K on it. I am getting a mysterious clunk-rattle that I am pretty sure is coming from the rear end.

When coasting a lower speeds (30ish) and hitting man-hole covers or potholes (any 'sharp' and abrupt bump) there is a audible clunk coming from the rear. The front end hits the bump and all sounds normal, but when the rear end hits the bump I get the racket. To describe the sound, think of a fender washer clunking in the bottom of a tin coffee can...loudly. It may be occurring at higher speeds I just can't hear it.

I am a pretty methodical person and have put a lot of effort into figuring this out and can't seem to get to the bottom of it. And it is driving me CRAZY!! I even had a toyota tech give it a once over for me...rode in the trunk heard the sound...poked around...asked me about all of the below and came up shrugging.

So I will explain what I know IS NOT the problem and why I think so to save us all some time:

Axle wrap: nope. I have All-Pro Expo leafs with their U-bolt flip kit (about 9 months old).
Blown shocks: nope. I just put in brand new Fox 2.0 remote resi's...it was making the sound before and after the swap...and yes they are tight.
Loose Leafs/Shackles: nope. checked 'em; all tight.
Loose U-bolts: nope. Tiggity tight.
Loose Spare: nope. It's not in the carrier (and yes the cable is tight up to the bed).
Loose hitch or ball in the hitch: nope. All-Pro's rear bumper and side plates with All-Pro's hitch (which is empty) and all of these pieces are tight.
Something in the pockets of the bumper: nope. Me checks!!1!
Slop in U-joints: nope. Has the normal (acceptable) amount of play and all are properly greased.
Rear Diff fluid: nope. Just changed it with conventional and LSD additive (2007 mechanical LSD)
Loose gas tank: nope. Or at least I don't think so...it's still attached and doesn't seem loose when hitting it with a rubber mallet (or kicking it out of frustration because you wish that was the problem!).
Play in rear drums: nope. Just bled 'em
Play in rear axle: nope. Both wheels (all 4 for that matter) feel secure side-to-side and roll without grinding or hang-ups.
Loose Leer topper: nope. toight like a tiger.
Loose gremlins in bedside pockets: nope. fresh out.

All kidding aside does anyone have any other ideas? I'm thinking I might crash it into a tree later this week if I can't figure it out...that should solve it.
Thanks for any input!

Cheers.

 

Sounds like you've modded your taco a bit...but I have a stock 2010 PR SR5 and that underbody cover rattles when I'm driving. You can hear it rattle when you close the doors as well.

 

Ummm? Underbody cover? Like the IFS bash guard up front? If that's what you're talking about then I don't think that's my problem. I have the All-Pro's plate front with the stock guard attached as well. I'm 99% sure this isn't the rattle...cause it's tight! and I only hear the sound when the rear hits.
Thanks for the suggestion though!

 

There's some like...shitty plastic covering underneath my bed. I don't know what the hell its called, but it rattles like crazy when I'm on rough roads.

 

Not sure...the bed is a molded plastic and is mounted directly to the frame with body mounts in-between IIRC. There are heat-shields around the exhaust, maybe that's what you're talking about, but those aren't my issue.

Anyone else got any other idears?

 

Don't laugh.... but check the junk you have in your storage compartments in the back seat.

And yes....Check your body/bed mounts. I had a clunk in the front end while driving on the highway and found my body mounts were far below 50ft lbs of torque.

 

Good call...I'll check the body mounts.
Thanks.

 

Buddy had this on tundra. Eventually would click when going from reverse to drive. He had a shop replace the driveshaft carrier bearing or can also be called driveshaft center support bearing. The noise was the driveshaft binding when it shortened. This fixed a very hard to diagnose clicking when the driveshaft extends or retracts like going over bumps as well as going from forward to reverse.

My truck does it a little. This might be your issue.

 

sound like this ?


http://s3.photobucket.com/user/sh311shock/media/VID00076_zps8a47c3bf.mp4.html
http://s3.photobucket.com/user/sh311shock/media/VID00079_zpsaf9bd3fd.mp4.html

 

I greased the slip yoke last summer. I'll take a look at that and do it again and see if thats it.

TwzteD...yes. Sounds very similar.

I'll see if I can post up and mp3 of the audio...

 

Uhh...I think I've done that right.

Listen to the attached...

 

Re-greased the slip yoke...that's not it! ...frustrated...

 

Had to add spacers to the bolts that held my bed down last year, just an idea to try.

 

I do have a go-pro...that's where the audio comes from.

It sounds very similar to what you hear in TwzteD's videos too.

TwzteD - Did you figure out what your problem was?

 

Good day gents,

Just wondering if this problem was ever solved. I have a similar clunk (not a rattle) coming from the rear suspension I think. I even hear a series of clunks when I turn off my driveway which is like a 4" dip! I tightened all bed bolts and body mounts and the u-bolts and the like are all tight. Spare is tight too.

What gets me is that this clunk is only there when the bed flexes laterally, ie left and right and not up/down. I can push & pull on the bed and get that annoying clunk! Weird...

 

So I posted the same question in the Suspension section in the Mid Travel thread. I posted a pic of my leafs and got a suggestion to 'seperate the leafs'. Basically the anti-friction pads at the ends of the leafs were keeping them seperated at the ends, but in the middle (between those pads and the center pin of the leaf on both sides front and rear) the leafs were resting on each other. Through the range of motion they were binding on each other and causing my rattle/squeak.

A quick way to test this would be to jack the body of the truck (to unweight the leaves) and stuff some pieces of rags inbetween. Then drive around and see if that stops it...that's how I figured out it was my problem. My, hopefully?, perminent solution was to take some rubber strips and place them inbetween each leaf. I did this yesteday, I glued the rubber to the top of the leaf and put grease on the bottom. Quiet as a mouse so far.

I am glad this is resolved but what a PITA!

Everyone complains about the stock leaves on these trucks, and I get it...they sag over time and can't cary a heavy load. But beware, it always seems to be my experience that modifying somthing introduces the posibility for more problems. Manufacturers have a wealth of knowledge base and experince. Chances are it was designed that way for a bunch of really good reasons.

All in all, I wouldn't change it. I like my lift and the 'capacity' with my set-up. Maybe AllPro should put more of the anti-friction pads in the middle of the leaves?

Thanks everyone for the suggestions/help!
-Dave

 

There shouldn't be anything in-between the leaves at the centering pins. Putting a pad there would eventually compress and the leafs would be loose. Not a good thing. If the leafs are loose at the centering pin - can eventually sheer off the centering pin.

Did you check your centering pin to make sure it was tight? And/or it could be stripped and coming loose.... Check your ubolts for proper torque also.

 

^^^ I'm not talking about where the centering pin is, but rather inbetween the pin and the ends of each leaf. AllPro's leafs actually have an aluminum shim inbetween each leaf at the centering pin. The pin is as tight as it needs to be. And yes the u-bolts (on the flip kit) are, and always have been, properly torqued.

And thanks, but nothing more needs to be checked...problem solved!

 

yea rear lower leafspring both sides were hittin the rest of the pack u can see the wear mark, i put a felt pad on each and it went away

 

Zombie thread from way back.

I have a clunky rattling coming from somewhere behind, under, or around the right back seat. It's fine on the highway but on a bumpy road it makes me want to strangle something, so annoying! I emptied everything out of the under- and behind- seat storage and the storage cubbies in the bed and still had the problem. When I did that though I noticed one of the bed mount bolts has almost a 1/8" gap between the bolt and the bed, so I took it to the Toyota dealership today and asked if they could try to tighten that down (it needs a weird star-shaped driver. God forbid we just use a Phillips?). They tried to tighten it but it was solid, even with the small gap. So I guess that's not it.

I do have a cover that protects the underside of the truck, maybe something is on that or it's missing a bolt? I'm skeered to crawl under the truck while it's on a jack (all I have is the bottle jack for changing the tires), so this should be an interesting check. Any ideas on that? Is it a difficult thing to check? I have a steep dropoff on one side of my driveway, maybe I could just pull the truck along the dropoff, it worked for checking under the back bumper for stuff.