Thunk sound from rear suspension, thoughts? - Toyota FJ Cruiser Forum
Suspension / Steering Tech All suspension and steering related topics belong in this subforum.

Reply
 
LinkBack Thread Tools Display Modes
#1 (permalink) Old 01-18-2013, 06:31 PM
Forum Regular
 
jays0n's Avatar
 
Join Date: Jan 2012
Location: Redmond, WA
Posts: 197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Thunk sound from rear suspension, thoughts?

Hey gang, this noise is starting to drive me mad so I'm gonna finally try to figure out what it is. When going over a bump, I get a sharp thud in the rear like something is loose. It seems to happen when the suspension unloads. It doesn't happen over all bumps. For example if I'm going slow over a good sized bump I get no noise but going fast I get it every time.

It has plagued me since putting in the 3" SAW lift. I also replaced the sway bar links about the same time so the bar should be back to near stock angles. Every since then this has been happening. I have triple checked that nothing is loose or out of place but can't figure it out. Did the lift change the geometry to a point that this is just what happens kinda thing or am I just missing something?

2007 Sun Fusion | 6MT 4x4 | Nitto Trail Grappler 285/70-R17 | Fuel Wheels | SAW 3" Lift | Total Chaos UCA's | RedEye Sway Bar Links | TOY Lower Links | TRD Short Shifter | Demello Front Bumper/Sliders | ExpOne Bumper w/swingout | Rotopax | TJM Winch | On-board Air | Rigid Industries Lighting | Rock Lights | Dual Battery | SPOD | MPAC Everything | Kenwood DNX9980HD | JL XD700/5 | JL 10W3v3 | FOCAL 6.5 coax | CST Interior | Dinoot Compact trailer w/solar, water, propane | Tepui Autana RTT
jays0n is offline  
Sponsored Links
Advertisement
 
#2 (permalink) Old 01-18-2013, 06:50 PM
Forum Superstar
 
CowboyCEO's Avatar
 
Join Date: Jul 2007
Location: East Bay, Nor Cal
Posts: 2,138
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Garage
Send a message via Yahoo to CowboyCEO
Lifetime Supporting Member
Re: Thunk sound from rear suspension, thoughts?

One time I had a "Thunk" back there. I was 90 miles out in the Mojave when I finally found the culprit. One side of my panhard bar lost it's bolt and it was bouncing off my BozTec diff skid.

Thank's again John

2,007 Sun Fusion / nickname "9-Ball" / Black Leather / K/N filter / Safari Snorkel / Flow master 40 series / 6sp M/T / Hella 550's / Ricochet Skids / Demello sliders/ Boztec diff skid, High Lift hanger and antenna mount / Fire stick / Uniden c/b / Glade Plug-in / Nitto Terra Grappler 285/70/17/, Fox 2 1/2" ext-travel coilovers with resi up front and Fox 2.0 piggybacks in the rear/ Total Chaos U.C.A.s/ Icon springs / All Weather Mats...




<a href=http://i580.photobucket.com/albums/ss245/cowboyceo/MrSpinnerScores2.jpg target=_blank>http://i580.photobucket.com/albums/s...nerScores2.jpg</a>
CowboyCEO is offline  
#3 (permalink) Old 01-19-2013, 06:43 AM
Forum Veteran
 
jtmroczk's Avatar
 
Join Date: Dec 2007
Location: Tampa Florida
Posts: 869
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Re: Thunk sound from rear suspension, thoughts?

The lift didn't change the geometry. Go back and put a wrench on every bolt you touched previously. Did you tighten your upper shock mounts a little more after putting the truck back on the ground?

Lifting does not remove the body mount from the path the tire takes through the wheel well. Lifting does not move that path around the body mount. Lifting only sets the starting point of that path partially below the body mount giving the illusion of clearance. Only alignment and body mount chop can increase tire clearance between the body mount and tire.

07'-10' Titanium Silver 2007 5at 4x2 - Trade-in
10'-14' Silver Fresco 2010 6mt 4x4 - Build Thread -Trade-in
Black 2005 G35 6mt
jtmroczk is offline  
#4 (permalink) Old 01-19-2013, 06:46 AM
Buggy Building Moderator
 
FJNewb's Avatar
 
Join Date: Apr 2008
Location: Houston, TX
Posts: 17,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Lifetime Supporting Member
Re: Thunk sound from rear suspension, thoughts?

Shouldn't be your link mounts otherwise you'd notice the axle steering your vehicle when you got on and off the gas. I'd look at your shocks, swaybar, and panhard
FJNewb is offline  
#5 (permalink) Old 01-19-2013, 08:31 AM
Forum Superstar
 
CowboyCEO's Avatar
 
Join Date: Jul 2007
Location: East Bay, Nor Cal
Posts: 2,138
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 5 Post(s)
Garage
Send a message via Yahoo to CowboyCEO
Lifetime Supporting Member
Re: Thunk sound from rear suspension, thoughts?

Oh, Check to see if your bottle jack is snug. If it is even a little loose it can make the described noise.

2,007 Sun Fusion / nickname "9-Ball" / Black Leather / K/N filter / Safari Snorkel / Flow master 40 series / 6sp M/T / Hella 550's / Ricochet Skids / Demello sliders/ Boztec diff skid, High Lift hanger and antenna mount / Fire stick / Uniden c/b / Glade Plug-in / Nitto Terra Grappler 285/70/17/, Fox 2 1/2" ext-travel coilovers with resi up front and Fox 2.0 piggybacks in the rear/ Total Chaos U.C.A.s/ Icon springs / All Weather Mats...




<a href=http://i580.photobucket.com/albums/ss245/cowboyceo/MrSpinnerScores2.jpg target=_blank>http://i580.photobucket.com/albums/s...nerScores2.jpg</a>
CowboyCEO is offline  
#6 (permalink) Old 01-19-2013, 09:32 PM
Member
 
ROVER1998's Avatar
 
Join Date: Mar 2008
Location: Knoxville TN
Posts: 67
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Lifetime Supporting Member
Re: Thunk sound from rear suspension, thoughts?

I am having the same problem. It sounds like metal hitting metal, and only happens when I go really fast. It's very annoying. I have the icon stage two, any guesses? There are times when it sounds like its coming from the front. I really can't pinpoint it.

Traded my 07 for 08. I went from silver to black.
Icon Stage 2, Supercharger, BFGAT 285/75/16, Ham radio, cb, blackout kit, trd wheels
ROVER1998 is offline  
#7 (permalink) Old 01-20-2013, 11:53 AM
Forum Regular
 
jays0n's Avatar
 
Join Date: Jan 2012
Location: Redmond, WA
Posts: 197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Re: Thunk sound from rear suspension, thoughts?

Bottle jack is very tight so that's not it. It almost sounds like it happens right AFTER the suspension absorbs the bump. I was unsure how tight the shocks should be, the instructions warned that too tight could cause problems so I tried to follow their instructions. I believe it was a turn or so after the washer stopped moving. Are they too loose? I never touched the panhard bar so I can't imagine that's the culprit. I did remove the sway bar mounts and replace the bushings with graphite impregnated polyurathane, could that be my problem?

2007 Sun Fusion | 6MT 4x4 | Nitto Trail Grappler 285/70-R17 | Fuel Wheels | SAW 3" Lift | Total Chaos UCA's | RedEye Sway Bar Links | TOY Lower Links | TRD Short Shifter | Demello Front Bumper/Sliders | ExpOne Bumper w/swingout | Rotopax | TJM Winch | On-board Air | Rigid Industries Lighting | Rock Lights | Dual Battery | SPOD | MPAC Everything | Kenwood DNX9980HD | JL XD700/5 | JL 10W3v3 | FOCAL 6.5 coax | CST Interior | Dinoot Compact trailer w/solar, water, propane | Tepui Autana RTT
jays0n is offline  
#8 (permalink) Old 01-20-2013, 11:57 AM
Buggy Building Moderator
 
FJNewb's Avatar
 
Join Date: Apr 2008
Location: Houston, TX
Posts: 17,526
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Lifetime Supporting Member
Re: Thunk sound from rear suspension, thoughts?

I'd go around with a wrench and make sure your fasteners are all tight. Starting there will be the first step towards identifying the problem
FJNewb is offline  
#9 (permalink) Old 01-20-2013, 01:34 PM
Forum Veteran
 
jtmroczk's Avatar
 
Join Date: Dec 2007
Location: Tampa Florida
Posts: 869
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Re: Thunk sound from rear suspension, thoughts?

Quote:
jays0n previously said: View Post
Bottle jack is very tight so that's not it. It almost sounds like it happens right AFTER the suspension absorbs the bump. I was unsure how tight the shocks should be, the instructions warned that too tight could cause problems so I tried to follow their instructions. I believe it was a turn or so after the washer stopped moving. Are they too loose? I never touched the panhard bar so I can't imagine that's the culprit. I did remove the sway bar mounts and replace the bushings with graphite impregnated polyurathane, could that be my problem?
I'm sure the shocks are fine then. You're right, don't over tighten, the stem mount can bend under dull compression if the bushing can't move enough.

Lifting does not remove the body mount from the path the tire takes through the wheel well. Lifting does not move that path around the body mount. Lifting only sets the starting point of that path partially below the body mount giving the illusion of clearance. Only alignment and body mount chop can increase tire clearance between the body mount and tire.

07'-10' Titanium Silver 2007 5at 4x2 - Trade-in
10'-14' Silver Fresco 2010 6mt 4x4 - Build Thread -Trade-in
Black 2005 G35 6mt
jtmroczk is offline  
#10 (permalink) Old 01-22-2013, 11:44 AM
Forum Regular
 
jays0n's Avatar
 
Join Date: Jan 2012
Location: Redmond, WA
Posts: 197
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
(Thread Starter)
Re: Thunk sound from rear suspension, thoughts?

I'll be warming it up in the garage tonight after work and going over all the fasteners again. The last time I did this I didn't find anything loose but will go through it all again. Has anyone ran into issues with the back door rattling at all? I really have no idea what it could be, this is driving me nuts!

2007 Sun Fusion | 6MT 4x4 | Nitto Trail Grappler 285/70-R17 | Fuel Wheels | SAW 3" Lift | Total Chaos UCA's | RedEye Sway Bar Links | TOY Lower Links | TRD Short Shifter | Demello Front Bumper/Sliders | ExpOne Bumper w/swingout | Rotopax | TJM Winch | On-board Air | Rigid Industries Lighting | Rock Lights | Dual Battery | SPOD | MPAC Everything | Kenwood DNX9980HD | JL XD700/5 | JL 10W3v3 | FOCAL 6.5 coax | CST Interior | Dinoot Compact trailer w/solar, water, propane | Tepui Autana RTT
jays0n is offline  
Reply

  Toyota FJ Cruiser Forum > Toyota FJ Cruiser Discussion > Suspension / Steering Tech

Quick Reply
Message:
Drag and Drop File Upload
Drag files here to attach!
Upload Progress: 0
Options

Register Now

In order to be able to post messages on the Toyota FJ Cruiser Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome