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BMW Drivetrain Vibration Under Load – Acceleration

October 18, 2010

This answer is applicable for many BMWs in addition to the one listed below.

car year: 1999
car model: 323i
When doing a strong but not overly aggressive acceleration from a stop I notice a slight driveline vibration sound and can feel it somewhat on the auto transmission lever. Once acceleration is removed and at a highway speed there is no apparent vibration heard or felt. Passenger in right seat or rear seats can not identify a location other than the area of the automatic transmission console area. Car has 138,000 single owner miles and has never been in any accident or had any mechanical failures. What would be your recommended DIY troubleshooting decision tree?

Your symptoms point to either a weak center bearing or a weak driveshaft coupler flex disc (guibo).  Either one of these will cause the vibration under load that you described.  The rubber in both of these assemblies can be weak enough to cause the vibration, but can still appear OK visually.  Obviously, any cracks in the rubber are reason for replacement as well.  Since you have to drop the driveshaft to do either of these, we would suggest doing both at the same time.  You will also need the gaskets and hardware for the muffler system, as this must be dropped in order to access the driveshaft (earlier models require the catalytic converter to be removed).

Driveshaft and axle parts (flex discs, center bearings, etc.). 
ID your vehicle to narrow the list:

Exhaust gaskets 99 323i:

  1. Jim Harvey permalink

    It appears the correct Driveshaft Coupler Flex Disc (guibo) part number for our 1999 323i w/auto trans is 26 11 1 209 168.
    However is the referenced center bearing also called a centering sleeve part number 26 11 7 526 611 in your catalog?

    Also when I try to order the two needed exhaust pipe to headers gaskets I get a part number 18 30 1 440 183 and a warning to verify this is the correct gasket for this model and year by asking Bavarian Otto.

    Also what would be the correct part number for replacement bolts for the two exhaust pipes to header gasketed interface?

    • Yes the proper flex disc is the # 26 11 1 209 168 (you may see other numbers referenced as well, do to part number supercessions).

      The Centering Sleeve (or guide bushing) # 26 11 7 526 611 is the bushing the installs into the nose of the driveshaft and it centers the forward end of the driveshaft on the end on the transmission output shaft. This should be replaced when a flex-disc is replaced.

      The center bearing, for your application, is # 26 12 7 501 257

      The # 18 30 1 440 183 gasket is correct, according to the BMW micro-film. We’ll fix our listing on that one (thanks for bringing it to our attention).

      The manifold to downpipe bolts are # 11 62 1 427 586 and the nuts are # 18 30 1 737 774

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