Richard,
I had this problem only worse and it was the gearbox switch that only
allows the OD to engage in 4th. I have not had a chance to see if this is
the problem, but it sounds like this could be your friends problem. Work
seems to be getting in the way of my entertainment.
>From Scott.........
Tom,
There are two switches that control power to the OD.
One on the dash, and one in the gearbox. The dash switch lets YOU switch
into OD;
the gearbox switch only lets the OD on in the proper gears. They must both
be closed
for the OD to engage (column switch on, AND car in 4th gear).=20
The gearbox switch is located on the top of the gearbox, on the left
(drivers) side.
It is a round doodad that screws into the top of the remote shifter
housing. There
is a fibre washer under the switch.=20
Again, the function of this switch is to tell the O/D when the car is in
4th gear
(or 3rd and 4th with early gearboxes). As you shift into 4th, the switch
closes
and power can flow to the solenoid (assuming the dash switch is closed
also) If
YOU try to engage OD in any other gear, this switch will interrupt power
and the
OD will not kick in.
Over time the brass tip of the switch wears away and as a result isnt long
enough
to mesh with the cam in the gearbox remote. As you drive, it bumps around-
in and
out and causes this symptom. To test the switch, make sure the column
switch is
OFF and then yank off the two wires to the switch on the gearbox and
temporarily
jump them together with a test lead (tape them up with electrical tape).
This effectively
defeats the gear lockout so DO NOT ENGAGE THE OD SWITCH ON THE DASH IN ANY
GEAR OTHER
THAN FOURTH, ESPECIALLY REVERSE!! (too much torque in the lower gears or
backing
up can trash the OD clutch.)
Get the car up to speed and into 4th gear. Switch the OD on and see what
happens.
If the OD still drops in and out, you have eliminated this switch from the
list
of culprits.
Happy hunting!
--Scott
=20
At 08:55 PM 9/16/97 -0400, Richard A. Boris wrote:
>Hi Everyone:
>
>Need the collective wisdom of the list for a overdrive problem. A fellow
>member of the MG Car Club-Long Island Centre ( John Morris) has
>experience the following characteristics with his 1974 MGB:
>
> =95 The overdrive engages normally.
> =95 Functions OK until requiring moderate to hard accel, then kicks-out,
>but re-
> engages with steady speed. =20
> =95 Functions fine at sustained speed or light accel.
> =95 Recently changed the oil.
>
>Any suggestions would help.
>
> Thanks: Rich Boris, 67B
>Roadster
>
>
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