Noisy Differential

[AlfaSpider]

My 330d has developed a bit of a whine over the past few years, it sounds like it's either the manual g.box or the diff but it only happens when there's slight load like cruising at 70. Ive changed all the oils but this made no difference. I don't think I'll do anything about it as I guess it's a new diff I need. Just wondered if this was a common problem?

[Gaygle]

If it's an E46, it is totally normal. It happens on pretty much everybodies car, like you said, at about 70mph with partial throttle. BMW released a TSB (Technical Service Bulletin) to fix it using butyl sticky strips to prevent the driveshaft resonation being transmitted to the passenger compartment.

[Gaygle]

Just found the TSB released by BMW:


33 02 00 November 2000

SUBJECT Rear Axle Differential Whine Noise

MODEL
E46 All with M52TUB25 engine and 5L40E (GM5) transmission up to 3/00 production

E46 All with M52TUB28 engine and 5L40E (GM5) transmission up to 9/00 production

E39 All with M52B28 engine and THMR1 (GM310R) transmission up to 9/98 production

E39 All with M52TUB28 engine and 5L40E (GM5) transmission up to 9/00 production

SITUATION A loud whine or howling noise may be heard in the passenger compartment at approximately 70 miles per hour with a light engine load.

CAUSE The meshing of gears in the rear axle differential generates a whine noise under the conditions described above which on some vehicles may be transmitted to the body via the drive shaft center bearing.

CORRECTION On a customer complaint basis only install a drive shaft center bearing insulation strip (butyl strip) BMW part number 26 12 7 511 140 to reduce the drive line noise which is transmitted to the vehicle body as outlined below.

PROCEDURE
1. Remove exhaust system (see repair manual group 18, section 18 00 020) and heat shields.

2. E46 only: Remove the three hold down bolts which secure the drive shaft to the transmission output flange.

Note: The E39 incorporates enough clearance with the center bearing removed from the body to perform the repair described below. Therefore it is not necessary to remove the drive shaft from the transmission output flange to perform this repair on E39 models.

3. Remove two hold down nuts for the center bearing.

Note: Mark the position of the center bearing before removal. Center bearing should be reinstalled in the same position during reassembly.

4. Lower the drive shaft.

Note: The drive shaft must be supported during repairs to avoid damage to the joints.

5. Remove protective paper from the noise reduction strip and install the strip (1) on top of the center bearing housing as shown in the picture below.

6. Important: Before raising the drive shaft back into the vehicle tunnel a thin coating of mineral based engine oil must be applied to the exposed (top) side of the strip.

This oil will allow the center bearing (with strip installed) to be pushed up into the center bearing tunnel thus preventing damage to the strip since this is a very tight fit. The strip must not be torn during installation.

7. E46 only: Reinstall the three hold down bolts which secure the drive shaft to the transmission output flange.

Note: New self locking nuts part number 07 12 9 900 047 must be used when reinstalling bolts. Torque specification: 100Nm (74 lb.ft.)

8. Reinstall center bearing nuts and torque to specification. Torque specification: 21Nm (15.5lb.ft.)

9. Note: When tightening the center bearing nuts the strip must squeeze out between the center bearing housing and the center bearing tunnel as shown in the picture below (see arrows). For this fix to be effective the center bearing must fit tightly into the center bearing tunnel with the noise reduction strip compressed when the nuts are torqued to specification.

10. Reinstall heat shields.

11. Reinstall exhaust system.

PARTS
INFORMATION

Part Number Description Quantity

26 12 7 511 140 Center bearing insulation strip 1
07 12 9 900 047 Self locking hex nut M12x1,5 (E46 only) 1

[AlfaSpider]

Yes my cars an e46, thats very reassuring to know that it's a common problem thanks for the advice. If it gets really annoying I might get round to fixing it! My cars done 130k now and will keep it running as long as I can I think the e46's are great cars.