That's exactly where the Healey ("A" type) overdrive engaged in reverse: in
my driveway at creep speed. I'm not trying to debate anyone or start an
argument, I'm just saying that this is the experience I had, personally,
back in 1972 or so with my '61 Austin Healey 3000.
Your hypothesis is well founded and well thought out but my experience with
the A-H prevents it becoming a theory.
From: John Duhart <firstname.lastname@example.org>
To: email@example.com <firstname.lastname@example.org>; email@example.com
<firstname.lastname@example.org>; email@example.com <firstname.lastname@example.org>
Date: Monday, May 18, 1998 1:10 PM
Subject: Re: TR6 overdrive.
> I knew this is the type of response I would get (well sort of). What I am
saying is not that an OD won't engage in reverse, but that it won't engage
in reverse unless you are driving at speed (i.e. enough speed to build up
400 psi in the OD). I don't think this would happen if all you are doing is
driving out of your driveway.
>>>> "Ed Woods" <email@example.com> 05/18 11:22 AM >>>
>Don't tell my '61 Healey 3000 that the o/d can't be engaged in reverse!
>Wired the lever into the closed position because the solenoid had failed.
>The o/d remained on in all gears, forward and reverse.
>I was on the interstate at the time the solenoid failed. Healey's are not
>made to be driven at 75mph in fourth gear; hence my temporary fix.
>From: John Duhart <firstname.lastname@example.org>
>To: email@example.com <firstname.lastname@example.org>; email@example.com
>Date: Monday, May 18, 1998 8:32 AM
>Subject: Re: TR6 overdrive.
>> Ya know, I've seen a lot of people asking this question, and I was
>thinking about it this week, and I came to a potentially interesting
>conclusion... The OD CANNOT engage in reverse, unless you are driving at
>> Let me explain. (Please rememer I have a self-thought knowledge of the
>so if you want to shoot this down feel free). OK, the OD needs pressure
>from the pump to be engaged. I've read that it needs about 400psi from the
>pump to function. I have read that one of the reasons both the A and
>OD's are locked out in 1st gear is because the pump cannot produce that
>of pressure. If this is true, then it should also not be possible to build
>up 400psi of pressure while drving in reverse out of your driveway, so the
>OD will not engage.
>> Now I can think of two possiblities were you could get the OD to engage
>>1) You drive in reverse for about a mile doing around 30-40mph. This may
>build up enough pressure
>>2) While driving down the highway you decide to through it into reverse to
>see what will happen, and forget to shut-off the OD. (Of course your OD
>exploding will be the least of your problems!)
>> Anyway I think this is why we have seen people reporting they have driven
>in reverse with the OD on without destroying it. These people were only do
>a short drive (i.e. out of the driveway), and at a very low speed, so the
>pump couldn't build up pressure to 400psi, and so the OD WAS NOT engaged.
>> What does everyone the.
>> (Yes another complex problem solved in the shower!)
>>>>> Bollen <firstname.lastname@example.org> 05/16 7:42 PM >>>
>>Today I tried to reverse with the O/D engaged. Luckily it does not seem
>>to have done any damage. (J type).Is there supposed to be any kind of
>>electrical lockout when reverse is engaged? I never did this before,
>>wondering if a wire has come off somewhere.
>>74 Tr6 80 TR8