Look in the Moss catalog on the page that shows the BN2-BJ8 Overdrive
exploded view. Item number 79 (PN 866-690) is an O-ring which seals the
accumulator housing to the OD body. Although the unit may have been
rebuilt, I'll bet those were not changed. If they leak the accumulator
will not maintain enough pressure to hold the OD in firm engagement
consistently, especially when the oil is hot. This will cause the
clutch to slip under acceleration.
My OD was doing the same thing and I cured it by replacing these
O-rings. (Later units use one ring while early ones use two.)
Removing the accumulator housing turned out to be fairly easy. Just
remove the side plate and solenoid then the plug on the actuator valve.
Then while using a piece of dowel or something similar to hold the
smaller piston in place, apply some air pressure to the actuator valve
port. It may take a few tries, but eventually the housing will pop out.
Good luck.
Bill Lawrence
On May 30, 2004, at 2:38 AM, Simonlachlan@aol.com wrote:
> You will recall my email concerning my BT7's new habit of jumping out
> of
> overdrive...
> ""One for the gurus....
> Background first:-
> I have all new overdrive mechanicals which worked fine until just
> recently.
> I have a 28% ratio o/d unit.
> Plenty of good clean oil in gearbox, first thing I checked.
> Overdrive on/off switch is new and works fine.
> Switch on gearlever is not new but works fine.
> I have not messed around with carbs or related linkage.
> Solenoid sounds healthy and engages overdive firmly.
> (I have a 3:54 diff, so the revs may seem a little low to you,
> especially
> coupled to a 28% o/d)
>
> So, the symptoms
> If I am driving along at about 1,900revs with my car in overdrive/4th,
> she'll jump out of overdrive if I raise the revs/speed with the
> accelerator.
> If I then decelerate back to 1,900 (+/-) she'll pop back into
> overdrive."
> The car has been off the road while some work was done on the
> instruments,
> so i could not provide feedback re. the many and excellent mails I
> received. So
> it was circumstance, not idleness....
> Well, I've done the obvious first thing and bridged the throttle
> switch on
> the bulkhead. The symptoms vanish. Where would I go now...? ....must
> the fault
> be in the throttle switch? First logic says yes, but how can the
> throttle
> switch disengage the unit while the relay is working?
> But, if the relay isn't working, how does it ever switch on in the
> first
> place?????????
> Simon.
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