The judder felt like a rotational wobble of something emanating from underneath the glovebox/rear of the console. The squeak also sounded like it was coming from this area.
The juddering was more on acceleration, and the squeaking more on deceleration. There was no loss of power, and the clutch wasn't slipping.
I did a bit of research and found it was most likely the 'guibo' (flexible disc on the propshaft), but there was a small chance it could be the centre baring on the propshaft also.
Armed with some research I got the car on the ramps and started investigating. The guibo looked completely fine, so puzzled I decided to delve deeper and remove all trim panels and the exhaust from the downpipe back.
It was fair to say I'd found the problem when I saw what's in the video below. The rubber boot in the centre bearing mount had completely disintegrated, providing no support at all to the propshaft. You can see my dad wobbling the propshaft, whilst he's doing so you can see straight through the gap where the rubber boot should be.
Unfortunately I needed the parts quickly as the car had to be on the road, so had to get the parts direct from BMW at what would most likely be an extortionate price.
I called up and got a quote, £92.15, that included the following all genuine BMW parts;
6x - p/n: 07129900047 - Description: Self-locking hex nut - M12 x 1.5 - 10 - PHR
1x - p/n: 26122282496 - Description: Aluminium Centre Mount, with Grooved ball bearing - D=55/D=35
1x - p/n: 26127511140 - Description: Butyl cord Terostat 2460 - 190mm x 20mm x 8mm
6x - p/n: 33217571990 - Description: Torx screw with ribs M10 x 46 - ZNS3
1x - p/n: 26122282496 - Description: Aluminium Centre Mount, with Grooved ball bearing - D=55/D=35
1x - p/n: 26127511140 - Description: Butyl cord Terostat 2460 - 190mm x 20mm x 8mm
6x - p/n: 33217571990 - Description: Torx screw with ribs M10 x 46 - ZNS3
A lot of the bolts in this area are one use only and I wasn't sure how many I would have to remove to do the job, so just bought a replacement for all of them for peace of mind that the job was well done.
All parts assembled I got straight to work, first job being to crack the nut joining both halves of the propshaft. This turned out to be easier said than done, a rather large spanner extension and some choice French words later it was removed. Three bolts hold the front section of the propshaft to the flexi disc, after removing these it could be removed from the car. Before removing it I marked it at both ends with white paint to make sure it went back in the same orientation, quite important for balancing reasons I believe.
Now the propshaft was separated the shot centre bearing could be removed. The bearing came away fairly easily and so did the rest of the assembly. Quite a lot of the butyl cord was left stuck to the chassis and as I had bought a replacement strip I cleaned all the old stuff off. It's horrible stuff that sticks to everything, so it took a little while to clean it up.
All cleaned I prepared the new bearing for fitting, applying the new butyl cord strip to the mounting bracket. It was also a chance to compare new with old to show how bad the old one was.
Everything now prepared, reassembly could begin. The remaining half of the propshaft had been supported by a length of strong wire, whilst suspended and with the brown packaging film on the butyl cord still fitted, the centre bearing was pushed into place.
Next the removed portion of the propshaft was refitted.
Propshaft back together, all the other nuts and bolts were replaced with fresh ones, and finally the rest of the car assembled.
Touch wood, since the work was carried out there has been no judder or squeaks, so hopefully it was caught just at the right time and work was done correctly.