Getting a rhythmic thumping noise from rear of car!
First thought it was the rear tires since they were down to the wear bars. So I replaced them today with new tires. It is still there as loud as ever and the sound increases and gets faster with the speed of the car. A few months ago I had a rear stud replaced. They said the hub had melted on to something else and they had to order a new hub or wheel bearing. Not sure as I am not a mechanic. What does this sound like to you???
2009 g8gt - rotofab cai, ported throttle body & FAST intake, 1 7/8s kooks shorties with 3 inch exhaust. 3600 circle D triple disc stall and tranni cooler, udp, hoosier 17 inch drag radials. 223/235 cam/gmpp Heads. HP Tuners. 416 with 11.3 to 1 compression.
best time: 11.47 @ 118.7 3000 feet da
best top end 119.4 4000 feet da
We need a little more information.
Does the thumping correlate with the wheel speed or the engine speed?
Describe the symptoms. Does putting on the brakes make it go away, etc.
You'll get a better answer that way
2008 MGM G8 GT - #615 of 888 - Premium/Sport - 12.6 @ 111 on stock tires
SHOW - Chromed Stock 19" Wheels - Color Matched Splash Guards - Debadged - G8 Tail Lights - GXP Diffuser - Painted Calipers - Red S/S Engine Bolt Kit - Under Hood Lights - too much Zaino
GO - ARH Long Tube Headers / Midpipes - Billet Catch Can - BMR Front / Rear Swaybars - Camaro 3.45 diff - Custom non-DOD Cam and Valvetrain - Homegrown PCM / TCM Tuning - K&N Filter - Pedders 'Fruit' Suspension - Red Yella Terra Intake - Stealth Airbox
ALSO - DashHawk 5.1 - Full Slide Passenger Seat - Infinity / Kicker / MTX Audio - LED Interior /Glovebox / Console Lights - Rear Remote Trunk Release
Are there little people in the trunk that want out mebbee ?
09 G8 GT in Stryker Blue
Mods
Go: Vararam CAI, SLP Headers, Magnaflow 12468 mid-muffler & PM-FL Axlebacks. Tuned by MAC Autosports of Parker, Colorado. FE3 Shocks N Struts.
Show: Little Trees US Flag Vanilla Scented Air Freshener; SLP G8 Firehawk wheels; tinted windows
The Track
Best 1/4: 13.969 @ 102.70 @ Pueblo Motorsports Park, w/ DA of 3921'.
The sound increases with the speed of the wheels. Speed. The rpm of the engine has nothing to do with the sound. Yeah, those litttle people can be loud. I am going to bring it to Pontiac tomorrow.
thump, thump, thump. rhythmic. if i go 60 it is louder than when i am going 30. also when i do put on the brakes i believe the sound does go away.
2009 g8gt - rotofab cai, ported throttle body & FAST intake, 1 7/8s kooks shorties with 3 inch exhaust. 3600 circle D triple disc stall and tranni cooler, udp, hoosier 17 inch drag radials. 223/235 cam/gmpp Heads. HP Tuners. 416 with 11.3 to 1 compression.
best time: 11.47 @ 118.7 3000 feet da
best top end 119.4 4000 feet da
Had a loose caliper bracket do that once...mebbe a u-joint is failing on ya.
09 G8 GT in Stryker Blue
Mods
Go: Vararam CAI, SLP Headers, Magnaflow 12468 mid-muffler & PM-FL Axlebacks. Tuned by MAC Autosports of Parker, Colorado. FE3 Shocks N Struts.
Show: Little Trees US Flag Vanilla Scented Air Freshener; SLP G8 Firehawk wheels; tinted windows
The Track
Best 1/4: 13.969 @ 102.70 @ Pueblo Motorsports Park, w/ DA of 3921'.
what about the litttle people theory??? ha ha
I had the pads replaced a couple of months ago also. The tech who did the work is going to be in tomorrow.
2009 g8gt - rotofab cai, ported throttle body & FAST intake, 1 7/8s kooks shorties with 3 inch exhaust. 3600 circle D triple disc stall and tranni cooler, udp, hoosier 17 inch drag radials. 223/235 cam/gmpp Heads. HP Tuners. 416 with 11.3 to 1 compression.
best time: 11.47 @ 118.7 3000 feet da
best top end 119.4 4000 feet da
Tech is going to drive it in a few hours. Definitely in the right rear where he worked on it before. The reason I know this is when I go into a right hand curve and the pressure is put on the left wheels there is no noise. As soon as the car straightens out there is noise.
2009 g8gt - rotofab cai, ported throttle body & FAST intake, 1 7/8s kooks shorties with 3 inch exhaust. 3600 circle D triple disc stall and tranni cooler, udp, hoosier 17 inch drag radials. 223/235 cam/gmpp Heads. HP Tuners. 416 with 11.3 to 1 compression.
best time: 11.47 @ 118.7 3000 feet da
best top end 119.4 4000 feet da
If it is side to side, when you take the weight of one side it is louder, and the weight on the other there is no noise, it is gonna be a hub bearing....they are covered under powertrain till 100,000miles.
-Ryan
2008 G8 GT IOM
Livernois Stage 1 cam, Livernois ported heads with CNC valve job, Kooks 1 7/8 LT's, Magnaflow axle backs, Fast LSXR, Roto-fab CAI, 160 thermostat, BMR front and rear sway bars, BMR rear cradle bushings, BMR rear diff. bushings and H&R springs. Tuned by RPM 428.34 hp and 406.44tq. Best time of 12.36@114.9 on Street tires.
Yes, we were both correct. It is a hub bearing. When we put it in the air the wheel was very loose. Also I noticed the car at the drag strip would pull to the right. Obviously there was some friction going on in the right rear. Lucky the darn thing did not fall off.
2009 g8gt - rotofab cai, ported throttle body & FAST intake, 1 7/8s kooks shorties with 3 inch exhaust. 3600 circle D triple disc stall and tranni cooler, udp, hoosier 17 inch drag radials. 223/235 cam/gmpp Heads. HP Tuners. 416 with 11.3 to 1 compression.
best time: 11.47 @ 118.7 3000 feet da
best top end 119.4 4000 feet da
yea, the rears are kinda a pain cause they are press in, make sure it gets installed using the correct press adapters and correct amount of tons, I think last one I installed I went between 8-9tons
2008 G8 GT IOM
Livernois Stage 1 cam, Livernois ported heads with CNC valve job, Kooks 1 7/8 LT's, Magnaflow axle backs, Fast LSXR, Roto-fab CAI, 160 thermostat, BMR front and rear sway bars, BMR rear cradle bushings, BMR rear diff. bushings and H&R springs. Tuned by RPM 428.34 hp and 406.44tq. Best time of 12.36@114.9 on Street tires.
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