[FastGpa]

So I'm chasing a driveline vibration...

2006 325i manual. 150,000 miles.

I have a vibration that I feel in my butt when I get to 50mph...that increases as speed increases. Below 50mph not that noticeable. If I'm cruising at 55mph or so and push in the clutch and coast, the vibration is still there. If I'm cruising at 55mph and take it out of gear, the vibration is still there. Engine idles smooth and I can run it to higher rpm in the lower gears with no vibration.

Of course I assume the usual suspects: Guibo and CSB. Also did some research and thought that a collapsed passenger motor count could cause metal on metal contact, and cause vibration.

I replaced my motor mounts and transmission mounts as a first step. No improvement.

I dropped all the under trays to attack the guibo and CSB, and they both looked brand new. The guibo had no cracks or tears, and the bolts were f'en tight. In fact the driveshaft looked to be in newish condition. So I didn't replace anything. No improvement.

I got all 4 tires rebalanced. No improvement.

When I put on my snow tires, I checked the wheel bearings for play and grinding. Everything was tight.

So now I'm thinking it might be the u-joint on the driveshaft. Anyone care to share their experience or thoughts on this?

[tuxaflux]

The vibration drops after long ride ?