[Mgs] Overdrive Noise/Shifting Problem
Paul Hunt
paul.hunt1 at blueyonder.co.uk
Wed Jan 30 01:54:47 MST 2008
Firstly there definitely should not be slippage in 2nd gear, as OD should
not be engaged in that gear and drive is through the locked one-way clutch,
not the linings. However if the one-way clutch has been damaged, which
happens if OD is still engaged when reversing, then it could well be
dependant on the linings which will tend to slip in the lower gears.
With some of the other symptoms it could well be that the lock-out switch is
bypassed or has been in the past and damaged the OD, or possibly sticking
closed occasionally but this latter would be extremely unusual. It's easy
to check the lockout switch - simply drive along in 1st or 2nd flipping the
manual switch in for a few seconds and out for a few seconds. If the revs
change as they should in 3rd and 4th, then the lockout switch is not doing
its job, pure and simple.
Max is correct in saying there is only one lockout switch, which only allows
OD to be engaged in 3rd and 4th (4th only on later American cars) and locks
it out in all other gears. On a 71 is should be on the left side of the
gearbox, with the reverse light switch (nothing to do with OD) on the right.
If the lockout switch is functioning correctly all this is highly unlikely
to be oil level. It could be caused by dirty oil and blocked filters.
Drain the oil from the gearbox and clean the filters. Then refill with ATF,
which is said to have cleaning properties. If that seems to fix things,
possibly after a while, drain, clean and refill again. 20W/50 engine oil is
the norm, although again some say that ATF works better in a marginal
gearbox i.e. one with some problems. Failing that, it will need removal,
stripping and rebuilding as there would appear to be a major mechanical
problem.
PaulH.
----- Original Message -----
> for the second time in about 6 months or so, i've put it in reverse, let
> out
> the clutch and all i get is a loud whine, no movement.
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