2007 GS with active suspension - what is causing the nasty rear end clunk?
My 2007 GS-450h is at Lexus for the second time for diagnosis and in warranty repairs for a rear end clunk. So far however, they have not found anything wrong with my car this time either. Both times a "super tech" has ridden with me and experienced this clunk on a test drive and agreed that something was indeed wrong and should be fixed. But then they have commented that the shocks look fine, no leakage, blah, blah, blah... Actually, the first time they aired my tires up to 44 psi and the problem did get way better, but everyone says too that this is too high a pressure to run all the time.
If anyone has some thoughts regarding what could be the cause of the following symptoms, please reply!
- When I go over a 2" sunken manhole cover in a flat road at about 40 mph, the right rear makes a nasty clunk; it is the sound that a suspension would make if it had "bottomed out" (clearly the suspension is not bottoming out, I'm just trying to accurately describe the type of clunking noise that is occurring)
- hitting bumps, speed bumps, etc. NEVER makes this noise; it seems that the clunk is related to when the suspension needs to extend, not just compress
- right rear has also clunked before when braking hard and turning right into a parking lot driveway
- left rear has never made this same sound
Thoughts and other comments:
- My GS has the active suspension which includes some kind of active element in the middle of the rear sway bar
- Car came with run-flats, but currently has normal high-performance summer tires on it
- Maybe the right rear strut is "topping out" due to an internal problem with the strut itself (bad rubber bumper, etc.)
- Some other models of Lexus have received updated (thicker) sway bar rubber bushings to help with various clunk noises (F-Sport front anti-sway bar support bushings)
2006 Lexus GS 300 AWD – Glacier Frost Mica - Black - ML Package
20" x 8.5" Status Knight Wheels Black with Machine Face | Bridgestone G-Force Tires 245/30/20 | BC Racing Coilovers | Carson Tuned Lip Kit | 3000k HID Fogs | Prestigious Society Navi/DVD Override Kit | 15% Tint | Black Roof and Window Trim
your tires are fine and that is way to much pressure.
the sway bar bushings where for the F-Sport, do you have these on your car?
are you fully OEM suspension or do you have lowering springs?
with your symptoms are you driving slow or fast? how about going slow down a really rough road? I had something similar to what your explaining and it would only happen while going slow. Normal speeds I never heard anything. Slow down a rough road sounded like it was going to fall apart. Mine turned out to be the control arm bushings.
to me it almost sounds like it could be your end links or a bushing.
lol have the tech ride in your trunk, battery will keep them warm, and see where the noise is coming from.
Do you have **** (Active Stablizer Suspension System) or AVS (Adaptive Variable Suspension) The clunk noise could be sway bar linkage as BinarJay stated, maybe you should try on turns and see if you hear the noise, I would think you would hear it then.
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I had a similar issue with my 06 GS430. I took it to the dealer, and they found that the noise is coming from the rear brake calipers. It was still under warranty, replaced for free and the noise went away....