Re: Diff lock problem

[luis@odf.ucsd.edu (Luis Patino)]

Jim Griffin wrote:


>Okay... here's the latest "problem" with the Syncro (a.ka. 4kq Avant).

>It will only go forward (or reverse) now if I have the center diff 
>locked (or the center and rear diffs locked). I can put it into gear, 
>but nothing happens. It just revs, and I hear a grinding/churning noise
>from the rear (or the center?).

I think that one of your rear CV joints is dead, (perhaps both). When
your differentials aren't locked they transfer the most torque to
the fastest spinning axle. If a wheel has a broken CV that axle is
disconected from the wheel; thus, encountering no resistance whatsoever,
it will spin freely robbing the other 3 axles of all their torque.
However, locking the center diff makes it into a solid connection, 
forcing it to transfer 50% torque to each front and rear axles, so now
you would have a FWD car with 50% of its original power (and a broken
rear axle spinning like mad with the other 50%!). Locking the rear might
give you a 3WD car with 75% power :) Thus, you can drive your car with
the locked diff(s). However, driving it like this will soon damage the
rear diff. Please let me know if I was right.

HTH

Luis

'85 4kq 136k mi