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Old 02-01-2012, 08:03 AM
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timfitz63 timfitz63 is offline
MT = Doppler Shifting
Location: Lorena & San Antonio, TX
 
Join Date: Aug 2010
Posts: 860
Mein Auto: 2007 X3 (MT)
Quote:
Originally Posted by cldchc View Post
these components are tested and certified for more than a year.
Which components...? The metal replacement gears...? I have no doubt that they'll last...

That's not the problem I'm talking about, though... The problem I'm describing would arise if mechanisms in the transfer case or xDrive system became jammed for some reason. BMW likely designed that gear to be made out of plastic for a reason other than just to save a few dollars in production costs (although that would have been an additional motivator for them...): it's probably supposed to fail if the system becomes jammed, thereby preventing damage to high-dollar components of the transfer case/xDrive system. A metal replacement gear is not likely to fail under those same circumstances, leading to potential damage to, or failure of, another (probably more expensive) system component -- like the actuator motor.

Now, acknowledging that it's easier said than done in this case, my opinion has become that it's ultimately better to seek out an original plastic gear for this repair, if it becomes necessary (and "pburnett's" 'quick-fix,' outlined at the beginning in this thread, does not do the trick). But folks are certainly free to use the metal replacement gear at their own risk; in most cases, it will probably work out fine for them -- unless they're unfortunate enough to 'win' the lottery where something binds in the transfer case or xDrive system...

Just trying to keep people educated about why some decisions (e.g., the use of a plastic gear inside a transfer case) are made in the world of engineering when on the surface, it seems as if they were made in the world of finance... Carry on...
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