Loud thump during hard acceleration in first gear
10-15-2014, 12:11 PM
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Loud thump during hard acceleration in first gear
2005 525i 6MT
This just started a few days ago. When I accelerate hard in first gear, It will sound and feel like I've run over something. Sometimes it will make 2 or 3 clunks in a row over the period of a second. (makes me think its caused by something rotating)
I noticed the shifter seems to jolt towards the passenger side when I hit the gas. I suspect engine/transmission mounts but I don't understand the clunk itself. Any suggestions?
Here's a video of it in action. It jolts the car enough to dislodge my camera
This just started a few days ago. When I accelerate hard in first gear, It will sound and feel like I've run over something. Sometimes it will make 2 or 3 clunks in a row over the period of a second. (makes me think its caused by something rotating)
I noticed the shifter seems to jolt towards the passenger side when I hit the gas. I suspect engine/transmission mounts but I don't understand the clunk itself. Any suggestions?
Here's a video of it in action. It jolts the car enough to dislodge my camera
10-15-2014, 04:40 PM
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I have a 2006 530xi 6MT. Now mine is AWD, so it may not be exactly the same. But, I've never seen my shifter move that much which accelerating. I haven't had any issues like you are having. It doesn't sound good and if I was you, I'd stop driving it until you figure it out.
10-16-2014, 01:44 AM
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My Ride: 2008 535i LCI with sports/premium package, Sports trans with paddle shifters, CF emblems, JB4 Software, Dinan Exhaust, Navigation, M5Tech body kit, Carbon wrap interrior trim and CIC Controller.
Have you looked at the tray mounts underneath?
12-07-2014, 07:20 PM
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Okay I finally was able to resolve the issue. It got worse and I was having a hard time trying to accelerate in first gear without hearing and feeling the clunk.
I removed all of the underbody plastics and mounted a camera under my car facing the tranny mounts as they were my first suspect. The video showed an abnormal amount of play and led me to believe they were indeed the cause. I purchased new mounts and removed the old ones to find they were in perfect condition, even at 200k miles.
It turns out they engineered a mount that was no longer prone to ripping in half as it has a solid metal tab that locks into the crossmember and prevents an overextension of the mount. Impressive to say the least.
After reassembly, I then moved to the motor mounts. I was unable to make the engine lift while stationary, most likely because I was scared of destroying the clutch in the process. I mounted a camera under my hood and took the car for a spin. To my surprise, the drivers side mount was toast. The engine was flopping around like crazy.
I removed the mount and inspected it to discover another nice feature... These too have a metal piece that prevents overextension of the mount. In fact, the clunk noise I was hearing/feeling seemed to be coming from the motor mount as it topped out on itself. Well done BMW.
The new motor mount completely solved the problem and thanks to the design of the part, even when broken, it prevented damage to surrounding parts
Thanks for the help!
I removed all of the underbody plastics and mounted a camera under my car facing the tranny mounts as they were my first suspect. The video showed an abnormal amount of play and led me to believe they were indeed the cause. I purchased new mounts and removed the old ones to find they were in perfect condition, even at 200k miles.
It turns out they engineered a mount that was no longer prone to ripping in half as it has a solid metal tab that locks into the crossmember and prevents an overextension of the mount. Impressive to say the least.
After reassembly, I then moved to the motor mounts. I was unable to make the engine lift while stationary, most likely because I was scared of destroying the clutch in the process. I mounted a camera under my hood and took the car for a spin. To my surprise, the drivers side mount was toast. The engine was flopping around like crazy.
I removed the mount and inspected it to discover another nice feature... These too have a metal piece that prevents overextension of the mount. In fact, the clunk noise I was hearing/feeling seemed to be coming from the motor mount as it topped out on itself. Well done BMW.
The new motor mount completely solved the problem and thanks to the design of the part, even when broken, it prevented damage to surrounding parts
Thanks for the help!
Last edited by defaz; 12-07-2014 at 07:31 PM.
12-08-2014, 07:20 AM
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My Ride: 2005 525i 6MT
Okay I finally was able to resolve the issue. It got worse and I was having a hard time trying to accelerate in first gear without hearing and feeling the clunk.
I removed all of the underbody plastics and mounted a camera under my car facing the tranny mounts as they were my first suspect. The video showed an abnormal amount of play and led me to believe they were indeed the cause. I purchased new mounts and removed the old ones to find they were in perfect condition, even at 200k miles.
It turns out they engineered a mount that was no longer prone to ripping in half as it has a solid metal tab that locks into the crossmember and prevents an overextension of the mount. Impressive to say the least.
After reassembly, I then moved to the motor mounts. I was unable to make the engine lift while stationary, most likely because I was scared of destroying the clutch in the process. I mounted a camera under my hood and took the car for a spin. To my surprise, the drivers side mount was toast. The engine was flopping around like crazy.
I removed the mount and inspected it to discover another nice feature... These too have a metal piece that prevents overextension of the mount. In fact, the clunk noise I was hearing/feeling seemed to be coming from the motor mount as it topped out on itself. Well done BMW.
The new motor mount completely solved the problem and thanks to the design of the part, even when broken, it prevented damage to surrounding parts
Thanks for the help!
I removed all of the underbody plastics and mounted a camera under my car facing the tranny mounts as they were my first suspect. The video showed an abnormal amount of play and led me to believe they were indeed the cause. I purchased new mounts and removed the old ones to find they were in perfect condition, even at 200k miles.
It turns out they engineered a mount that was no longer prone to ripping in half as it has a solid metal tab that locks into the crossmember and prevents an overextension of the mount. Impressive to say the least.
After reassembly, I then moved to the motor mounts. I was unable to make the engine lift while stationary, most likely because I was scared of destroying the clutch in the process. I mounted a camera under my hood and took the car for a spin. To my surprise, the drivers side mount was toast. The engine was flopping around like crazy.
I removed the mount and inspected it to discover another nice feature... These too have a metal piece that prevents overextension of the mount. In fact, the clunk noise I was hearing/feeling seemed to be coming from the motor mount as it topped out on itself. Well done BMW.
The new motor mount completely solved the problem and thanks to the design of the part, even when broken, it prevented damage to surrounding parts
Thanks for the help!
12-09-2014, 09:36 AM
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My Ride: 2005 525i 6MT
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