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Old 09-07-2011, 04:16 PM
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Join Date: Feb 2008
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Mein Auto: 2004 X3 2.5i
Quote:
Originally Posted by timfitz63 View Post

But I think what's happening is that these plastic gears are not durable enough; they either have a weak spot or just get 'chewed up' by the metal worm gear over time. I'm actually rather shocked that BMW even used plastic cogs inside a transfer case, but...
I was surprised that even garage door opener motors have those nylon worm drive gears.

Recently took apart one - same sort of thing. The plastic just gets badly chewed up in one section.

The repair guy said it happens randomly, through bad luck.
They otherwise work fine for well over 10 years.

As you say, a weak point in the plastic, or maybe things get slightly out of alignment and the damage is started.

May be the same for the transfer case actuator - some will have that problem, but not inevitable.
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