Someone in the UK (where I live) sent me this. It seems that US cars are not affected but it's my first lead :-
Could this be the fault?
An intermittent cracking or clunking noise can be heard when the steering
is turned at low speed or when manoeuvring
Production period concerned: E65/E66: Start of series production up to week
E60/E61/E63/E64, all right-hand-drive vehicles.
The only left-hand-drive vehicles (LHD) affected are vehicles with an N62 engine:
Start of series production up to week 26/04.
Important:The E60,E61, E63 and E64 are only affected by cause 2. Thus only measure 2 provides a solution. Carry out measures 1 and 3 only on the E65/E66.
1. The tightening torque of the bolt securing the bottom of the steering spindle to the universal joint with corrugated tube has changed.
2. A gentle cracking noise from the telescopic toothing at the bottom of the steering spindle may be produced when the steering wheel is turned or when the steering column height is adjusted. This noise is caused by a slip-stick effect.
3. Burring can be detected on plastic bearing rings manufactured between 12/03 and 04/04. This burring can result in a cracking or grinding noise in individual cases.
Concerning cause 1: Replace the Torx bolt securing the bottom of the steering spindle to the universal joint with corrugated tube and tighten it to a torque of 28 Nm (refer to current EPC for Torx bolt). The torques in TIS are being updated accordingly.
Concerning cause 2: Treat the telescopic toothing on the steering spindle with a lubricant spray. BMW part number: 83 22 0 397
Concerning cause 3: Fit a new plastic bearing ring, BMW part
number 32 30 6 756 512 (see Repair Instructions 32 31