[Prev][Next][Index][Thread]

Thumping noise in drivetrain

>>>>> Original Message >>>>>

1. Centre bearing/centre bearing housing.  This is the bearing that joins 
the front driveshaft to the rear section of the driveshaft.  Its located 
above the exhaust about in the centre of the car.  The rubber surrounding 
the bearing goes south and the bearing floggs around in the housing. 
 Possibly not this because the drive shaft really thumps the driveshaft 
tunnel quite hard when you first take off.

2. Universal joints.  This is a killer.  Your problem might be worn 
unijoints at either the diff end or the tranny end OR BOTH :-(

<<<<< Reply <<<<<

The universal joints are not that hard to replace.  I have done
dozens of them and it doesn't require a rebalance of the
driveshaft and certainly not a replacement of the driveshaft.  The
only time I ever had to replace a driveshaft was when the shaft
itself was physically damaged (i.e. bent).

If anyone would like to know how to replace the universal joints
in the driveshaft, let me know and I will post the procedure (as
well as I can remember it after 20 years!).

Just to put in my two cents worth, Matt's original "thumping"
problem sounds a lot like a bad center bearing to me.  Just for
the record, when the center bearing goes bad, the driveshaft does
not actually hit the tunnel.  What you feel is just a vibration of
the driveshaft at low speed under load due to the shaft being
somewhat unbalanced by the misalignment of the two halves of
the shaft caused by the bad center bearing.


Don Mies
85 635CSi (The latest of 8 BMWs) - Wonderful car!!
Thinking (very hard) about a Z3