Rear Differential - Whine Noise
Group 33Rear Axle
Bulletin Number
33 02 00
Woodcliff Lake, NJ
November 2000
Service Engineering
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 SL40E (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.
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: 100 Nm (74 lb.ft.)
8. Reinstall center bearing nuts and torque to specification. Torque specification: 21 Nm (15.5 lb.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 (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:
Warranty Information:
Covered under the terms of the BMW New Vehicle Limited Warranty.