> Problem: I have serveral symptoms here, so I'll just list them then
> give my theories. I have a slipper clutch. When I have the clutch
> gear in my hand and hold it by the hex nut in the center, I can spin
> the gear freely. Is that normal in a slipper clutch? Isn't that the
Right... just need to clarify a few things here.
Have you got a motor in the car when you do this? Is the slipper actually
in the car or are you literally holding the slipper in your hand?
Take the motor out, and have the rest of the transmission built. Hold
the wheels still (if you're sitting down with the car on the floor, put one
on each wheel). Now grab the spur gear (wrap your thumb and finger
round the outside) and try to turn it, forwards for preference though it
doesn't really matter. It should be pretty stiff to turn, but when
finally slips it should be the slipper not the diff (watch carefully to see
turning). Adjust the hex nut until you can just about slip it. If the diff
really easily then tighten it up.
> mechanism that we get the slipper part? My big symptom is demonstrated
> when I turn the axles. I turn one wheel forward and the other one
> turns forward. I don't believe that's normal as my friend's wheels
> turn opposite of one another. When I hold down the clutch gear with my
> fingers and turn the wheel, the wheels spin opposite directions. With
Right... this all depends on how much resistance you've got where (like
there's a motor fitted). With no motor, I'd hope there's more resistance in
diff than there is in the drivetrain, so turning one wheel forwards ought to
the whole thing forwards just as you say.
With a motor fitted, or holding the spur gear (your "clutch gear", I
the diff will start to operate. Now, the two main points of a diff are:
1) it applies the *same torque* to each wheel (not strictly true for a
diff, but we'll ignore that for the moment).
2) it makes the *average speed* of the two wheels *equal* to the speed
of the drivetrain/input.
2) is the important one here. If there's a motor in or you're holding the
then the speed of the drivetrain is zero. If one wheel is spinning
for the average wheel speed to be zero the other wheel must spin *backwards*
at the same speed.
> the freedom of the axles as they turn. They are very stiff and don't
> glide very smoothly. I cleaned up the bushings (bearing upgrade will
> be soon) and all parts external to the transmission to no avial. I
> took the *** apart to see what was happening but saw nothing that
> looked weird (like I know what I'm looking for or something).
Right, first off take the motor out again and spin the whole transmission
forwards (you said it'll do this by turning one wheel, right?) Spin it and
let it go - the whole thing should carry on spinning for a couple of
maybe. If it stops immediately you've got problems, but on bushings slowing
down fairly quickly is normal (the bearings will help). Also if it feels
or stiff, it's time to start taking things apart and testing each bearing /
individually until you trace the one that's causing the problem.
Then hold the spur gear still once more, and turn one wheel so the diff
Now if *this* feels notchy or rough, it might be worth rebuilding the diff
although I'm not convinced that it really makes much difference - it's
not as important as having a smooth, free-running transmission.
Bear in mind that some real racecars (Le Mans/IMSA; Indycars) run with
no diff at all (a 'spool') at many circuits - the diff ain't essential!
> My Theory: The differential is going out. That would cause the axles
> to be tight and rough, as well as explaining the wheel-turning
> problem. The clutch gear is fine, but may require more *** "brakes"
> in it to keep things from slipping.
Certainly *sounds* like you may have your slipper too loose, but it's
hard to say (you didn't describe what happens when you drive the car...)
I'm not sure about "*** brakes" - all the slippers I've seen run teflon-
-coated metal pads against a plastic (probably nylon) spur gear. Just
tighten it up a little...
Sorry this has got a bit long - let us know how you get on.