August 11, 2013

Car Talk

Why does second gear always seem to fail first?

Syndicated columnists

Dear Tom and Ray:
Why is it that it always seems to be second gear that fails first in a manual transmission? I have been perusing my local Craigslist ads for cheap cars for a while now, and it seems to me, from the listings, that this is the problem gear. Is it due to the setup of most transmissions? If so, what type of standard transmission would cause this? Or is it due to driver error coming out of first? Just curious. — Matthew

Tom: I think it's a supply-and-demand issue, Matthew.

I agree that second tends to be the gear that often fails first on a manual transmission. It's probably because it's engaged more often than any other gear.

Tom: Think about it: You shift into second more often than you shift into anything else. You engage second every time you shift out of first. You shift into second every time you downshift from third or fourth. And because it's such a useful, low-speed gear, you choose it a lot, particularly if you do in-town or city driving.

So those synchronizers — which are brass rings that keep the gears from clashing when you shift — simply get more use, and tend to wear out before the others.

It's not always second that fails, and we certainly do see other gears go first. But generally speaking, all other things being equal, it's the synchronizers in the lower gears that get more wear and tear. So, in this case, second is first.

(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)


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