[Andy198712]

Hi,

2010 325d E91 RWD 150k miles
Recent PS4/5 tyres and balance.
Reasonably recent shocks and suspension overhaul.

This first happened on a long drive at cruise control 70mph. Felt like I drove over very rough tarmac or rumble strips and slowly increased.
I slowed to about 50 and it slowly went away then stayed away for the rest of the 200 mile trip.

A month later (had only done shorter trips in the mean time)
Did 240 mile drive last night, no issues
Came back today. Same drive same speeds 70mph
I got this vibration about 3 times.

Again, feels like rumble strips I can feel it in the car and the seat.

It’s an auto, knocked it into N and no change. Tried speeding up and slowing down and it just changed the vibration. Slowed to about 50 and it faded away

Then back up to 70 and all good for about an hour till it did it again.

Accelerates fine.
Not engine dependant.
Doesn’t seem to be brakes.


Does this sound like the centre bearing starting to go? And getting some resonance going on and getting worse till I drop enough speed to stop it and then it smoothes out?
Or more the rubber flex disc?

Cheers
Andy

[Andy198712]

Had a look under the car today, checked front and rear rubber flexis and the centre bearing, gearbox mounts and suspension parts

The rear flex has cracks in it which is going to be my first thing to change as the rest looked okay, front flex looked good, couldn’t feel play in the centre bearing or the UJ’s
I could deflect the rubber in the centre bearing a very small amount but I espected this as it’s rubber.

Here a pic,

[Andy198712]

And yes my diff input seal does weep but not enough to cause a drip yet, level has always been okay