Vibrations only under load and in gear (engine or driveline issue)

330ci · 01-13-2024, 01:10 AM

2007 BMW 320i Automatic (GM 6 speed transmission - GA6L45R)
Odo: 100k miles (~162,000km)

I’ve been having vibrations under moderate to high load coming from the front of the car, and you can feel it through the cabin (mostly front) and front seat. It only happens when it’s in gear (Drive selected). There's pretty much no vibrations with light throttle like when I’m demanding low torque and accelerating slowly. Vibrations tend to start happening when the revs are over 2000rpm and happens all the way to redline (vibrations get louder/worse with higher rpm).

Doesn’t have anything to do with speed I’m going at so doubt this is to do with wheels/tyres. And to address the common issue with the 6speed GM transmission, I don’t have any shuddering and I have just had the filter and fluid replaced (also added 2oz of Lubeguard instant shudder fixx). Servicing the transmission made absolutely no difference other than possibly making shifts slightly smoother.

As for engine mounts, I have had bad engine mounts before on several cars but they have all usually caused vibrations at idle and usually smoothed out when I rev the engine. My issue currently is the opposite - there are no vibrations at idle or if I rev engine while in park, and it vibrates in gear over 2000rpm. I also replaced all the spark plugs and there was no difference.

As for trans mounts and guibo, I haven’t checked these but I doubt these are the culprit.

At the moment this is what I’ve thought the issue could be:

Transmission and Torque converter - possibly but I've got no shudder
Engine mounts - possibly but I've got no vibrations at idle and the vibrations get worse with more revs
Trans mounts - possibly but doesn't seem to be worn
Wheel/tyres - very certain it's not this
Guibo - possibly but high doubt it since it's such low km and happens in any gear
Driveshaft, U-Joint or CSB - doubt this is the issue and vibrations feel like it comes more towards the front of the car
Diff - pretty certain it's not this. I've replaced this with a good used unit due to scraping/grinding diff bearing noise.
Exhaust - I've never had this issue before so not sure if it is possible
Suspension - highly doubt this is the cause. have also replaced all thrust arm bushings and front struts recently.
Brakes - highly doubt this is the cause

Bims328i · 01-13-2024, 08:45 PM

Really difficult to say. Usually if it's the center support, that typically shakes around when you first take off then clears up. You've pretty much pointed out a lot of stuff most would inspect.

I guess it would be worth it to check the trans mounts and guibo.

01-13-2024, 01:10 AM	#1
330ci New Member 0 Rep 9 Posts Drives: 2017 BMW M240i (F22 LCI) Join Date: Aug 2022 Location: Australia iTrader: (0)	Vibrations only under load and in gear (engine or driveline issue) 2007 BMW 320i Automatic (GM 6 speed transmission - GA6L45R) Odo: 100k miles (~162,000km) I’ve been having vibrations under moderate to high load coming from the front of the car, and you can feel it through the cabin (mostly front) and front seat. It only happens when it’s in gear (Drive selected). There's pretty much no vibrations with light throttle like when I’m demanding low torque and accelerating slowly. Vibrations tend to start happening when the revs are over 2000rpm and happens all the way to redline (vibrations get louder/worse with higher rpm). Doesn’t have anything to do with speed I’m going at so doubt this is to do with wheels/tyres. And to address the common issue with the 6speed GM transmission, I don’t have any shuddering and I have just had the filter and fluid replaced (also added 2oz of Lubeguard instant shudder fixx). Servicing the transmission made absolutely no difference other than possibly making shifts slightly smoother. As for engine mounts, I have had bad engine mounts before on several cars but they have all usually caused vibrations at idle and usually smoothed out when I rev the engine. My issue currently is the opposite - there are no vibrations at idle or if I rev engine while in park, and it vibrates in gear over 2000rpm. I also replaced all the spark plugs and there was no difference. As for trans mounts and guibo, I haven’t checked these but I doubt these are the culprit. At the moment this is what I’ve thought the issue could be: Transmission and Torque converter - possibly but I've got no shudder Engine mounts - possibly but I've got no vibrations at idle and the vibrations get worse with more revs Trans mounts - possibly but doesn't seem to be worn Wheel/tyres - very certain it's not this Guibo - possibly but high doubt it since it's such low km and happens in any gear Driveshaft, U-Joint or CSB - doubt this is the issue and vibrations feel like it comes more towards the front of the car Diff - pretty certain it's not this. I've replaced this with a good used unit due to scraping/grinding diff bearing noise. Exhaust - I've never had this issue before so not sure if it is possible Suspension - highly doubt this is the cause. have also replaced all thrust arm bushings and front struts recently. Brakes - highly doubt this is the cause Last edited by 330ci; 01-13-2024 at 01:19 AM..
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01-13-2024, 08:45 PM	#2
Bims328i DIYer 271 Rep 307 Posts Drives: 2008 328i E90 SULEV Join Date: Jul 2020 Location: United States iTrader: (0)	Really difficult to say. Usually if it's the center support, that typically shakes around when you first take off then clears up. You've pretty much pointed out a lot of stuff most would inspect. I guess it would be worth it to check the trans mounts and guibo.
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