Subject: Re: Understanding a 4-Speed Trans
Author: Eric Lamberts
Date: Oct 24, 2002, 6:44 PM
Post ID: 1711268029
On Thu, 24 Oct 2002, Keith Ruff wrote:
| Was thumbing through my 70's vintage Chilton manual and came across the trans. I was wondering how the trans actually operates, how it selects the different gears. Pic shows an "assembled 4 speed transmission" drawing. The "layshaft" which goes to the driveshaft, has 4 gears on it and 2 arm looking things, one on each side of the 2 inside gears with one gear outside of each arm. Then there is the "mainshaft" which also has 4 gears on it that appears to mate directly with the 4 gears on the layshaft. Next there is the shaft that goes to the clutch, the one that the actuator arm pushes on in the center of the rear case (aka plunger) that I just replaced the O-ring on - it came out with the throwout bearing magnetically attached. The final shaft is attached to the gear selector. What I don't understand is what happens to select the gear? I see that the clutch handle pushes the plunger which then will disengage the clutch, and the book says that the gear selector rotates the other shaft which then selects a different gear, but I don't follow that part. What is also confusing is that the 4 gears on the layshaft and mainshaft are in perfect alignment, indicating that all gears are turning at the same time, so how are the different gears selected. Highly confused here. |
The gears are in constant mesh, but in neutral at least one of each pair
that are engaged are not hooked to the shaft. The shifter forks slide
the gears back and forth on the shaft--there are dogs on the sides of the
gears that engage with the shaft to lock it in place to transmit power.
Check out:
www.dansmc.com/gearbox.htm
Kind of interesting, because loopers use neither of the 3 types of mc
gearboxes listed
Eric Lamberts ew-@unr.edu Reno NV