The flex disc, aka guibo, for the 540i, 740i, 840i, and Z8 connects the driveshaft to the transmission and provides a buffer to absorb driveline vibrations. The rubber flex disc takes the torque coming out of the transmission and delivers a seamless transition to the driveshaft. But over time the rubber is subjected to constant loading/unloading and it will break down. The rubber is designed to be the weakest link so that the rest of the driveline lasts longer.
Fitment note: E34 540i is for 6-speed manual only.
Symptoms of a failed guibo will be a dull thunk when dipping in/out of the throttle and during shifts. You may also notice cracks in the rubber around the bolt holes. A great time to replace the guibo, and driveshaft center support bearing, is during a clutch overhaul, short shift kit install, or any time the driveshaft is removed from the car.
This is a Genuine BMW 540i/740i/840i flex disc with a two year warranty. Buying a Genuine part will usually be more expensive than an OEM or aftermarket brand but you are assured that it meets BMW's designs for fitment, performance, and longevity. It will also be the very latest design, incorporating any updates or revisions that an aftermarket brand typically will ignore.
We also recommend replacing the 6 self-locking nuts at the same time.
Install note: the flex disc is directional. During install, look for an arrow on the outer rim. The arrow should point towards the flange and indicates the direction the bolt should go. Installing it backwards will cause premature failure of the flex disc.
E34 (89-95) > 540i
E39 (97-03) > 540i
E32 (88-94) > 740i
E32 (88-94) > 740iL
E38 (95-01) > 740i
E38 (95-01) > 740iL
E38 (95-01) > 750iL
E31 (91-97) > 840Ci
E52 Z8 (00-03) > Z8 Roadster (2000-2003)