Quote:
Originally Posted by sugarwood
Does the 915 fundamentally differ from modern gearboxes? Or does it have more in common with a modern gearbox than you'd think? More specifically, synchros.
Is the 915 meant to be operated in a fundamentally different way than a G50 or a Sentra gearbox? When I shift my 915 gearbox, I don't force it. Sometimes, if I feel a resistance, I lightly maintain pressure on it, and then it slides into gear. I understand this to be normal. Would this also be the case in a G50 or Sentra? Or are they totally different?
Is this attributed to the synchro? Does the synchro (or something else) need to speed up to match or something? Does this not apply to modern gearboxes? Is the 915 part of the "Syncromesh" paradigm? What about "dogbox" ? Is dogbox even more primitive than the 915 ? Or is the 915 a dogbox style gearbox? Where does the G50 and a 2005 Sentra gearbox fit into all this?
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Manual transmissions since the 50s have had syncros on most gears (sometimes not on #1).. My old 901 was syncromesh.
I suspect the syncros on your 915 are a bit worn, but are still doing their job.
Dogboxes are not necessarily more primitive, there are no syncros. Here's a pretty good explanation from superstreet dot com.
"Dog engagement is normally used in racing applications where fast, precise shifting is needed. Dog gear engagement is facilitated by numerous large teeth (dogs) that mate into matching openings machined into the opposite surface of the drive gear. Unlike the synchro engagement, there is no synchronizing mechanism to assist in equalizing speed. Ideal gear selection—e.g. minimal clashing and wear of the dog rings—is achieved by quick shifts; the motto here is “the quicker the better”, so bang away."
Best
Les