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      12-02-2009, 04:14 PM   #28
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Originally Posted by J08M3 View Post
Most syncros I know of are brass, or some material softer than the gears, this way any grinding that happens damages the syncro not the gear.
I don't think the synchros have teeth; do they? So they only wear if you push/pull on the knob while driving, no?
Only collars and gears (not the teeth but the 'female' dogs) seem to be able to grind. Now the question is if both the collar and gear could be damaged while grinding, or one is supposed to 'sacrifice' itself for the other . When a gear 'jumps' back to neutral, means the collar 'dogs' are rounded from grinding, and can't keep itself mated to the gear. I guess it doesn't matter if it's just one or both components, as tranny has to be opened up in that case. And although gear teeth are unaffected, the affected gear has to be replaced anyway due to worn dogs.

My new question is how synchros can wear prematurely if knob is never held while driving. Hopefully both the gears and collars are strong enough to withstand some abuse, as it's practically impossible not to grind a gear at least a few times in the life of the tranny. Thank you all for your contributions .