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Re: Overdrive woes

To: "Max Heim" <mvheim@studiolimage.com>, "MG List" <mgs@autox.team.net>
Subject: Re: Overdrive woes
From: paul.hunt1@virgin.net
Date: Fri, 23 Jun 2000 16:44:49 +0100
Steady on old chap (<g> noted), I wasn't telling you how it worked  -
witness the "If *you* can make the o/d cut in and out by pulling the gear
lever around a bit".  However mea culpa on "in that case you would need to
include 'reverse'", I suppose I should have used "one" instead of "you".
But where did 'lockout' switch come from?  The factory called it an
'overdrive gear switch'.  Incorrect oil can certainly cause problems, but
since Chris Delling had already said he was using the factory recommended
20W/50 ...

And I'll keep a look out for a "red one with the silver bootlid" over the
next couple of weeks!

PaulH.

----- Original Message -----
From: Max Heim <mvheim@studiolimage.com>
To: MG List <mgs@autox.team.net>
Sent: Thursday, June 22, 2000 6:40 PM
Subject: Re: Overdrive woes


> Well, excuse me <g>. I know perfectly well how the OD switch functions,
> but doesn't it  strike you as odd why it is called a 3rd-4th "lockout"
> switch when it does not "lock out" the OD in 3rd-4th, it "locks out" the
> OD in all other gears, speaking functionally (not mechanically). I left
> out reverse because, well, "duh"...
>
> As for the oil issue, don't you think it might be relevant to the
> problem? I believe I have previously heard reports of OD problems caused
> by using too light or too slippery a lubricant. At least one respondant
> claimed changing the oil solved his problem.
>
> paul.hunt1@virgin.net had this to say:
>
> >The chat about the oil is rather by-the-way for the original poster, and
the
> >switch closes in 3rd and 4th rather than opening in 1st and 2nd.  I
suppose
> >it could be taken to be like the old glass half full/half empty thing,
but
> >in that case you would need to include 'reverse' with '1st-2nd',
> >particularly since disabling the o/d in reverse it the most important
> >function of the gearbox switch.
> >
> >If you can make the o/d cut in and out by pulling the gear lever around a
> >bit while in 3rd or 4th it is almost certainly the gearbox switch.  Do
you
> >have the gear-lever mounted manual switch?  If so be aware that the
wiring
> >to these can give trouble because of the continual waggling about.
> >
> >PaulH.
> >
> >----- Original Message -----
> >From: Max Heim <mvheim@studiolimage.com>
> >To: MG List <mgs@autox.team.net>
> >Sent: Wednesday, June 21, 2000 4:40 PM
> >Subject: Re: Overdrive woes
> >
> >
> >> Hmmm, could it be temperature related? My understanding is you should
use
> >> single weight motor oil in the OD transmission. I use 30wt. Or...
> >>
> >> ...possibly the 1st-2nd lockout switch is flaking. Either the switch or
a
> >> wire connecting to it is opening temporarily, maybe related to
vibration
> >> at that RPM. Tough to get at the switch in a '77, though...
> >>
> >> delling3 had this to say:
> >>
> >> >I have a MGB fitted with a LH type overdrive.  I recently started
having
> >a
> >> >problem with the overdrive "cutting out", and am looking for some
help.
> >> >
> >> >Symptoms are noticable in either 3rd or 4th while in overdrive.  While
> >> >cruising under moderate load - not accelerating hard, or lugging at
low
> >> >R.P.M., the overdrive will begin to drop out.  It is an intermittant
> >> >situation, the engine will load up momentarily as the overdrive drops
> >out,
> >> >then the RPMs fall again just as quickly.  The symptoms occur only in
> >> >overdrive (the clutch isn't slipping), and seems to be possibly
> >influenced
> >> >by either R.P.M. (around 3500 R.P.M. engine speed) or temperature
(more
> >when
> >> >car has been run for a while).
> >
> >
> >
>
>
> --
>
> Max Heim
> '66 MGB GHN3L76149
> If you're near Mountain View, CA,
> it's the red one with the silver bootlid.
>
>


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