Re: Nasty tranny slop?? (r32redneck)
Doesn't matter that it's cable linkage. If you can feel vibration through
the shifter then it's coming from the far end of the cable, which is connected
to the shifter arm on the tranny. The shifter arm is connected
to the gear selector forks which is connected to a ring between
each pair of synchronizers called a collar. The synchros are always spinning
at the same speed of the output shaft. The collar that connects to the
selector fork is not, which means there's a bearing between them.
(edit: In some cases there isn't even a bearing. There's just a ring
with a slot in it and the selector fork slides in the slot.)
That bearing is meant to take a thrust (side load) only while
you're selecting and deselecting gears (by sliding the
spinning synchro and dog teeth until they mesh with the
dog teeth on the side of each regular gear).
Once the gear as been selected, there is not supposed to be a thrust
load the collar as it'll wear out the bearing (same as if you
left your foot on the clutch pedal all the time it'd wear out the
throw-out bearing and sometimes the engine's main bearing).
Also the gear selector fork usually terminates in two little fingers that
rest lightly in a groove in the collar. If there's any sustained pressure
between the fingers and the collar then vibration of the engine/tranny
causes increased wear between fingers and collar and the
shifter gets physically sloppier over time.
Keep in mind there are no physical stops to the shifter arm in
the tranny. The only thing that stops it from moving further is when
the collar's dog teeth engage the selected gear's dog teeth and the
collar can't be slid any further. The "stop" you feel is a thrust load
on the collar's bearing.
And I'm not saying you can't rest your hand on the shifter when
you're rowing through the gears (although a racer will tell you
it's still better to put your right hand back on the wheel between shifts
for full control). It's just that the practice of resting your hand
on the shift knob all the time is generally frowned upon, for
the reasons I've outlined above.
See the diagrams on this page
http://auto.howstuffworks.com/transmission3.htm
for more info. (Note, the animated diagram is really cool looking
but the gear speeds are all wrong, and the synchro rings should
be spinning, but aren't, which is unfortunate because
it would *really* help people understand how tranny's work
if they could get that right)
ian
Modified by Daemon42 at 11:08 PM 2-3-2007
Modified by Daemon42 at 11:53 PM 2-3-2007
