BM-41 Ticking

February 27, 2008, TCRA Email Forum

I built a BM-41 for an Audi, It had the crimped in style captive clutch. We did the usual, remove piston, replace clutch and O-ring, and replace clutch. We TIG weld the clutch once it is back in place. The customer is complaining of a ticking noise that is RPM dependent. The customer bought a brand new ZF converter and the tick/noise went away. I cut the converter open and clutch did not come loose. The turbine seems to have plenty of clearance, so I don’t think it is hitting the welds. Any ideas???

Chris Sehorn
Circle D Specialties
Houston, Texas

Yes we have had this.  In our case the hub had worn where the pump gearrides and this allowed the gear to be sloppy.  In our case new hub fixed theproblem.  You also need to be really fussy with alignment.Martin Brooks

 I was going to ask what kind of run out you had.
Mark Mustard

Runout was .005 to .007 from what I remember, I cut it last week. It was a factory hub. I have also checked the OEM runout and have seen over .010. But I agree, these seem to be very sensitive units.


When you say factory do you mean factory new or factory used?  In our casethe factory used was the issue.


Factory used, but no signs of wear. I have also replaced the hubs with new Sonnax hub and had a whine.