This bulletin applies to 2002 BMW 745i vehicles. A loud whine or howling noise may be heard in the passenger compartment at approximately 70 mph to 80 mph with a light or no engine load (when coasting).
Meshing of the rear axle gears generates a whine noise which on some vehicles may be transmitted to the body.
On a customer complaint basis only, install a new optimized driveshaft that incorporates a two-stage universal joint (disc on the transmission end) and a new style transmission output flange. The new style driveshaft and output flange was phased into production on 10/14/2002.
26 10 7 526 500………E65 driveshaft with two-stage joint
26 10 7 526 496………E66 driveshaft with two-stage joint
24 20 7 526 637………Transmission output flange
26 11 1 229 122………Bolt, M12 x 1.5 x 68.5 (3 needed)
07 12 9 900 047………Nut, M12 x 1.5 (3 needed)
26 11 1 227 843………Nut, M10 (6 needed)
When fastening the two-stage universal joint to the transmission output flange, do not tighten the bolts/nuts from the bolt head. Torque the nut while holding the bolt stationary, to 66 ft.-lbs. Turning the bolt in order to tighten the nut will cause the two-stage joint bushings to distort, creating further drive line vibrations and/or noises.
Torque specification for the 10 mm driveshaft nuts at the differential flange is 52 ft.-lbs.
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