On Oct 18, 12:22*pm, Jules Richardson
wrote:
The reversing gear on my elderly (pushing 25 years now) lawn tractor's
getting a little stubborn - at least while the engine's running; it seems
happy switching between forward and reverse when the engine's stopped.
Google turned up a few incidents of this same problem, but unfortunately
I didn't see any actual solutions.

There doesn't seem to be any significant wear on the gears / dog clutches
within the diff. Everything stops turning with the clutch pedal pressed,
but I *think* what's happening (given the way it works OK with the engine
stopped) is that pushing the clutch isn't fully releasing tension on the
transmission (and therefore the input shaft to the diff). With the engine
running, if I really haul on the forward/reverse lever while "tickling"
the clutch pedal, it'll usually work - but I suspect that I'll eventually
break something doing that...

Question is, are there any "usual suspects" to look at? I can adjust the
rod which connects the clutch pedal to the arm containing the dual-cone
drive clutch (which serves as the transmission's gearbox) so that it
travels further and therefore slackens the belts more - but I'm reluctant
to mess with it if the problem's likely elsewhere, as I assume that
messing with that will also result in belts potentially slipping during
normal drive.

Another possibility: The gearbox side of things operates fine, which
means that the conical clutch is able to slide up and down on its shaft
as it's supposed to, but maybe this isn't sliding as well as it should
(and so although tension is removed on the belt which links the engine to
the clutch, it's not being removed adequately on the belt which links the
clutch to the diff)?

(the mower's an old MTD/Craftsman with 38" deck and 11HP B+S vertical-
shaft engine, not that it probably matters as I bet the drive
arrangement's typical for all sorts of lawn tractors, even if the parts
are slightly different)

cheers

Jules

When this problem occurs in an automobile with manual transmission, it
is usually the transmission input shaft bearing in the flywheel. With
age, wear and no lubrication, the bearing begins to behave like a
sprag clutch and when the input shaft is turning the gears simply
don't want to behave. Something similar could be happening in this
case.

Joe