Tow starting

rads · Apr 27, 2005

'Bout a week ago, the Rangie failed to start. No starter, no clicks,
no dimming of the headlights, nothing.

After a bit of fiddling, kicking, bypassing the solenoid etc, she
started, and for the hundred or so times I have started her since, has
started perfectly.

Being financially cautious (mean), and a born optomist, I'm just
putting this down to the old girl having an off day, and am trying to
put it behind us, but deep in my heart I know the starter / solenoid
is on its way out and will pick the midnight on Dartmoor to pack up
completely.

So, question is, can I tow start an Auto Rangie (4 speed, no viscous
diff)?

I think if the car is over 40mph, and I take my foot off the
throttle, drop it into neutral and then back into drive, the revs do
rise as if the transmission is backdriving the engine, making a tow
start possible.

Does this actually work in practice? What is the technique, leave
gearbox in drive and have tow car accelerate until "something" in the
gearbox locks up and starts to spin the engine? What is that
"something" anyway? I'm pretty sure that below 40mph ish the
transmission does not backdrive the engine, and remember vague talk
about "top gear lock up".

TIA

David

SimonJ · Apr 28, 2005

> So, question is, can I tow start an Auto Rangie (4 speed, no viscous
> diff)?
>
No.

> I think if the car is over 40mph, and I take my foot off the
> throttle, drop it into neutral and then back into drive, the revs do
> rise as if the transmission is backdriving the engine, making a tow
> start possible.
>
> Does this actually work in practice? What is the technique, leave
> gearbox in drive and have tow car accelerate until "something" in the
> gearbox locks up and starts to spin the engine? What is that
> "something" anyway? I'm pretty sure that below 40mph ish the
> transmission does not backdrive the engine, and remember vague talk
> about "top gear lock up".
>
The gearbox is operated by oil pressure generated when the engine is
running, if the engine is not running, there is no oil pressure, so none of
the clutches will engage, so no drive.

Austin Shackles · Apr 28, 2005

On or around Wed, 27 Apr 2005 23:25:57 +0000 (UTC), "SimonJ" <[email protected]>
enlightened us thusly:

>
>> So, question is, can I tow start an Auto Rangie (4 speed, no viscous
>> diff)?
>>
>No.
>
>> I think if the car is over 40mph, and I take my foot off the
>> throttle, drop it into neutral and then back into drive, the revs do
>> rise as if the transmission is backdriving the engine, making a tow
>> start possible.
>>
>> Does this actually work in practice? What is the technique, leave
>> gearbox in drive and have tow car accelerate until "something" in the
>> gearbox locks up and starts to spin the engine? What is that
>> "something" anyway? I'm pretty sure that below 40mph ish the
>> transmission does not backdrive the engine, and remember vague talk
>> about "top gear lock up".
>>
>The gearbox is operated by oil pressure generated when the engine is
>running, if the engine is not running, there is no oil pressure, so none of
>the clutches will engage, so no drive.
>

The only boxes I know this works on is the borg-warner 35 - which had 2
pumps, one on the output shaft and one on the input shaft - and the
AP/lockheed 4-speed as fitted to the mini which had a special valve you
could operate to allow it to tow-start.

The 'box will indeed drive the engine, once the engine's already turning;
it'll do so in any gear and give more engine braking in lower gears,
although it'll never have as much engine braking as a manual, since the
torque converter also works backwards and allows some slip.

the way it disengages is something to know about as well - if you're using
the engine braking (most commonly off-road) and something happens that kills
the engine, it'll continue to slow down until the point at which the 'box
drops out of gear, whereupon it'll roll freely. If you don't realise it's
going to do that, it can catch you out.

If you do what you just described, (on a quiet road) and once you have it
rolling in neutral, turn the engine off, you'll find that it won't restart.
Be careful 'cos you also lose the power steering...

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
Satisfying: Satisfy your inner child by eating ten tubes of Smarties
from the Little Book of Complete B***ocks by Alistair Beaton.

Richard Brookman · Apr 27, 2005

So rads was, like

> So, question is, can I tow start an Auto Rangie (4 speed, no viscous
> diff)?
>
No. Tried it on my 3.9, up to about 40mph, in and out of Drive, nothing. I
could not get the engine to turn at all. I stopped before I knackered
anything.

--

Rich

Pas d'elle yeux Rhone que nous

hugh · Apr 29, 2005

In message <[email protected]>, Austin Shackles
<[email protected]> writes
>On or around Wed, 27 Apr 2005 23:25:57 +0000 (UTC), "SimonJ" <[email protected]>
>enlightened us thusly:
>
>>
>>> So, question is, can I tow start an Auto Rangie (4 speed, no viscous
>>> diff)?
>>>
>>No.
>>
>>> I think if the car is over 40mph, and I take my foot off the
>>> throttle, drop it into neutral and then back into drive, the revs do
>>> rise as if the transmission is backdriving the engine, making a tow
>>> start possible.
>>>
>>> Does this actually work in practice? What is the technique, leave
>>> gearbox in drive and have tow car accelerate until "something" in the
>>> gearbox locks up and starts to spin the engine? What is that
>>> "something" anyway? I'm pretty sure that below 40mph ish the
>>> transmission does not backdrive the engine, and remember vague talk
>>> about "top gear lock up".
>>>
>>The gearbox is operated by oil pressure generated when the engine is
>>running, if the engine is not running, there is no oil pressure, so none of
>>the clutches will engage, so no drive.
>>
>
>The only boxes I know this works on is the borg-warner 35 - which had 2
>pumps, one on the output shaft and one on the input shaft - and the
>AP/lockheed 4-speed as fitted to the mini which had a special valve you
>could operate to allow it to tow-start.
>
>The 'box will indeed drive the engine, once the engine's already turning;
>it'll do so in any gear and give more engine braking in lower gears,
>although it'll never have as much engine braking as a manual, since the
>torque converter also works backwards and allows some slip.
>
>the way it disengages is something to know about as well - if you're using
>the engine braking (most commonly off-road) and something happens that kills
>the engine, it'll continue to slow down until the point at which the 'box
>drops out of gear, whereupon it'll roll freely. If you don't realise it's
>going to do that, it can catch you out.
>
>If you do what you just described, (on a quiet road) and once you have it
>rolling in neutral, turn the engine off, you'll find that it won't restart.
>Be careful 'cos you also lose the power steering...
>
I had a 1968 Austin 1100 auto (4 speed box) which could be tow started.
--
hugh
Reply to address is valid at the time of posting

Badger · Apr 30, 2005

"hugh" <hugh@[127.0.0.1]> wrote in message
news:[email protected]...
>>
> I had a 1968 Austin 1100 auto (4 speed box) which could be tow started.
> --
> hugh

That's 'cos it was the same AP Lockheed box as the mini.
Badger.

hugh · May 1, 2005

In message <[email protected]>, Badger
<[email protected]> writes
>
>"hugh" <hugh@[127.0.0.1]> wrote in message
>news:[email protected]...
>>>
>> I had a 1968 Austin 1100 auto (4 speed box) which could be tow started.
>> --
>> hugh
>
>That's 'cos it was the same AP Lockheed box as the mini.
>Badger.
>
>
But what was technically different about it compared to todays boxes
which appear not to want to be tow started?
--
hugh
Reply to address is valid at the time of posting

Badger · May 1, 2005

"hugh" <hugh@[127.0.0.1]> wrote in message
news:[email protected]...
> In message <[email protected]>, Badger
> <[email protected]> writes
>>
>>"hugh" <hugh@[127.0.0.1]> wrote in message
>>news:[email protected]...
>>>>
>>> I had a 1968 Austin 1100 auto (4 speed box) which could be tow started.
>>> --
>>> hugh
>>
>>That's 'cos it was the same AP Lockheed box as the mini.
>>Badger.
>>
>>
> But what was technically different about it compared to todays boxes which
> appear not to want to be tow started?
>

The design of older boxes wasn't as clever hydraulically as the modern ones,
hence the need for 2 pumps instead of one, the "rear" pump having an output
proportional to roadspeed, I think, giving an equivalent pressure signal to
the modern governor valve unit. A by-product was that when sufficient
pressure was built up by the car rolling, you could drive the engine, unlike
the modern ones that need the engine turning to give any pressure at all.
That's how I understand it, anyway, but if someone else has a better
explanation then I'm all ears.
Badger.

JD · May 1, 2005

Badger wrote:

>
> "hugh" <hugh@[127.0.0.1]> wrote in message
> news:[email protected]...
>> In message <[email protected]>, Badger
>> <[email protected]> writes
>>>
>>>"hugh" <hugh@[127.0.0.1]> wrote in message
>>>news:[email protected]...
>>>>>
>>>> I had a 1968 Austin 1100 auto (4 speed box) which could be tow started.
>>>> --
>>>> hugh
>>>
>>>That's 'cos it was the same AP Lockheed box as the mini.
>>>Badger.
>>>
>>>
>> But what was technically different about it compared to todays boxes
>> which appear not to want to be tow started?
>>
>
> The design of older boxes wasn't as clever hydraulically as the modern
> ones, hence the need for 2 pumps instead of one, the "rear" pump having an
> output proportional to roadspeed, I think, giving an equivalent pressure
> signal to the modern governor valve unit. A by-product was that when
> sufficient pressure was built up by the car rolling, you could drive the
> engine, unlike the modern ones that need the engine turning to give any
> pressure at all. That's how I understand it, anyway, but if someone else
> has a better explanation then I'm all ears.
> Badger.

That's basically it! No rear pump, no tow start - and most boxes do not, and
never had have rear pumps. The rear pump was never fitted to allow tow
starting (tow starting is not a design criterion) but to improve efficiency
or drive-ability.
JD

hugh · May 2, 2005

In message <[email protected]>, JD <[email protected]> writes
>Badger wrote:
>
>>
>> "hugh" <hugh@[127.0.0.1]> wrote in message
>> news:[email protected]...
>>> In message <[email protected]>, Badger
>>> <[email protected]> writes
>>>>
>>>>"hugh" <hugh@[127.0.0.1]> wrote in message
>>>>news:[email protected]...
>>>>>>
>>>>> I had a 1968 Austin 1100 auto (4 speed box) which could be tow started.
>>>>> --
>>>>> hugh
>>>>
>>>>That's 'cos it was the same AP Lockheed box as the mini.
>>>>Badger.
>>>>
>>>>
>>> But what was technically different about it compared to todays boxes
>>> which appear not to want to be tow started?
>>>
>>
>> The design of older boxes wasn't as clever hydraulically as the modern
>> ones, hence the need for 2 pumps instead of one, the "rear" pump having an
>> output proportional to roadspeed, I think, giving an equivalent pressure
>> signal to the modern governor valve unit. A by-product was that when
>> sufficient pressure was built up by the car rolling, you could drive the
>> engine, unlike the modern ones that need the engine turning to give any
>> pressure at all. That's how I understand it, anyway, but if someone else
>> has a better explanation then I'm all ears.
>> Badger.
>
>That's basically it! No rear pump, no tow start - and most boxes do not, and
>never had have rear pumps. The rear pump was never fitted to allow tow
>starting (tow starting is not a design criterion) but to improve efficiency
>or drive-ability.
>JD
Well, the box on the 1100 was superb - and 4 speed in those days was
revolutionary on an auto, all the others were 3 speed.
--
hugh
Reply to address is valid at the time of posting

Badger · May 2, 2005

"hugh" <hugh@[127.0.0.1]> wrote in message
news:[email protected]...
> In message <[email protected]>, JD <[email protected]> writes
>>Badger wrote:
>>
>>>
>>> "hugh" <hugh@[127.0.0.1]> wrote in message
>>> news:[email protected]...
>>>> In message <[email protected]>, Badger
>>>> <[email protected]> writes
>>>>>
>>>>>"hugh" <hugh@[127.0.0.1]> wrote in message
>>>>>news:[email protected]...
>>>>>>>
>>>>>> I had a 1968 Austin 1100 auto (4 speed box) which could be tow
>>>>>> started.
>>>>>> --
>>>>>> hugh
>>>>>
>>>>>That's 'cos it was the same AP Lockheed box as the mini.
>>>>>Badger.
>>>>>
>>>>>
>>>> But what was technically different about it compared to todays boxes
>>>> which appear not to want to be tow started?
>>>>
>>>
>>> The design of older boxes wasn't as clever hydraulically as the modern
>>> ones, hence the need for 2 pumps instead of one, the "rear" pump having
>>> an
>>> output proportional to roadspeed, I think, giving an equivalent pressure
>>> signal to the modern governor valve unit. A by-product was that when
>>> sufficient pressure was built up by the car rolling, you could drive the
>>> engine, unlike the modern ones that need the engine turning to give any
>>> pressure at all. That's how I understand it, anyway, but if someone else
>>> has a better explanation then I'm all ears.
>>> Badger.
>>
>>That's basically it! No rear pump, no tow start - and most boxes do not,
>>and
>>never had have rear pumps. The rear pump was never fitted to allow tow
>>starting (tow starting is not a design criterion) but to improve
>>efficiency
>>or drive-ability.
>>JD
> Well, the box on the 1100 was superb - and 4 speed in those days was
> revolutionary on an auto, all the others were 3 speed.

Yes, not a bad little box in its day, but I always felt it changed up a tad
too quickly. More reliable than the Borg-Warner 35T/A fitted to the princess
though, that's for sure!
Badger.

JD · May 2, 2005

Badger wrote:

>
> "hugh" <hugh@[127.0.0.1]> wrote in message
> news:[email protected]...
>> In message <[email protected]>, JD <[email protected]> writes
>>>Badger wrote:
>>>
>>>>
>>>> "hugh" <hugh@[127.0.0.1]> wrote in message
>>>> news:[email protected]...
>>>>> In message <[email protected]>, Badger
>>>>> <[email protected]> writes
>>>>>>
>>>>>>"hugh" <hugh@[127.0.0.1]> wrote in message
>>>>>>news:[email protected]...
>>>>>>>>
>>>>>>> I had a 1968 Austin 1100 auto (4 speed box) which could be tow
>>>>>>> started.
>>>>>>> --
>>>>>>> hugh
>>>>>>
>>>>>>That's 'cos it was the same AP Lockheed box as the mini.
>>>>>>Badger.
>>>>>>
>>>>>>
>>>>> But what was technically different about it compared to todays boxes
>>>>> which appear not to want to be tow started?
>>>>>
>>>>
>>>> The design of older boxes wasn't as clever hydraulically as the modern
>>>> ones, hence the need for 2 pumps instead of one, the "rear" pump having
>>>> an
>>>> output proportional to roadspeed, I think, giving an equivalent
>>>> pressure signal to the modern governor valve unit. A by-product was
>>>> that when sufficient pressure was built up by the car rolling, you
>>>> could drive the engine, unlike the modern ones that need the engine
>>>> turning to give any pressure at all. That's how I understand it,
>>>> anyway, but if someone else has a better explanation then I'm all ears.
>>>> Badger.
>>>
>>>That's basically it! No rear pump, no tow start - and most boxes do not,
>>>and
>>>never had have rear pumps. The rear pump was never fitted to allow tow
>>>starting (tow starting is not a design criterion) but to improve
>>>efficiency
>>>or drive-ability.
>>>JD
>> Well, the box on the 1100 was superb - and 4 speed in those days was
>> revolutionary on an auto, all the others were 3 speed.
>
> Yes, not a bad little box in its day, but I always felt it changed up a
> tad too quickly. More reliable than the Borg-Warner 35T/A fitted to the
> princess though, that's for sure!
> Badger.
My memory is a little hazy, but wasn't the AP gearbox design different from
most automatics?
JD

Austin Shackles · May 3, 2005

On or around Mon, 2 May 2005 12:06:09 +0100, hugh <hugh@[127.0.0.1]>
enlightened us thusly:

>Well, the box on the 1100 was superb - and 4 speed in those days was
>revolutionary on an auto, all the others were 3 speed.

me dad was working for AP at the time that was designed. Not sure how much
hand he had in designing it mind.

--
Austin Shackles. www.ddol-las.fsnet.co.uk my opinions are just that
"Festina Lente" (Hasten slowly) Suetonius (c.70-c.140) Augustus, 25

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