Disco 2 Auto Transmission

Just got my first Auto (Disco 2 TD5 - 2001 MY).

On a slope I thought an Auto should not roll back when in 'D' but mine
doesn't hold at all. Is this normal or is there a problem? The slope is
reasonable but not too steep.

Andy

Andy wrote:
> Just got my first Auto (Disco 2 TD5 - 2001 MY).
>
> On a slope I thought an Auto should not roll back when in 'D' but mine
> doesn't hold at all. Is this normal or is there a problem? The slope is
> reasonable but not too steep.
>
> Andy
>
>
Is that with the engine running or stationary? Either way, no, it
won't. When running, you can hold the vehicle on the footbrake with the
left foot whilst keeping revs up with the right (if necessary, e.g. for
a hill start). When stationery, that's what P is for!

Stuart

Srtgray wrote:
> Andy wrote:
>> Just got my first Auto (Disco 2 TD5 - 2001 MY).
>>
>> On a slope I thought an Auto should not roll back when in 'D' but
>> mine doesn't hold at all. Is this normal or is there a problem? The
>> slope is reasonable but not too steep.
>>
>> Andy
>>
>>
> Is that with the engine running or stationary? Either way, no, it
> won't. When running, you can hold the vehicle on the footbrake with
> the left foot whilst keeping revs up with the right (if necessary,
> e.g. for a hill start). When stationery, that's what P is for!
>

The Rangie does. Im sure old Disco1 auto boxs do. Id check with the dealer..

Theres a girl with one here at work, Ill ask.

Andy wrote:
> Just got my first Auto (Disco 2 TD5 - 2001 MY).
>
> On a slope I thought an Auto should not roll back when in 'D' but mine
> doesn't hold at all. Is this normal or is there a problem? The slope is
> reasonable but not too steep.
>
> Andy

All autos seem to drive different. Some of mine would hold on a gentle
hill, feet off all pedals in D, some wouldn't. My '98 Rangie which I
think has virtually the same ZF 'box as your Disco will creep forward
on the level in drive, and will also hold on a gentle hill. The
downside to a vehicle that holds on a hill is it creeps forward on the
flat so you need to keep the brake on! So long as yours is driving and
changing smoothly, there's nothing to worry about.

Alan C

<[email protected]> wrote in message
news:[email protected]...
>
> Andy wrote:
>> Just got my first Auto (Disco 2 TD5 - 2001 MY).
>>
>> On a slope I thought an Auto should not roll back when in 'D' but mine
>> doesn't hold at all. Is this normal or is there a problem? The slope is
>> reasonable but not too steep.
>>
>> Andy
>
> All autos seem to drive different. Some of mine would hold on a gentle
> hill, feet off all pedals in D, some wouldn't. My '98 Rangie which I
> think has virtually the same ZF 'box as your Disco will creep forward
> on the level in drive, and will also hold on a gentle hill. The
> downside to a vehicle that holds on a hill is it creeps forward on the
> flat so you need to keep the brake on! So long as yours is driving and
> changing smoothly, there's nothing to worry about.
>
> Alan C
>

Drives OK, just wondered if there was some sort of 'clutch' in an auto that
could wear with age?

In message <[email protected]>, Andy
<[email protected]> writes
><[email protected]> wrote in message
>news:[email protected]...
>>
>> Andy wrote:
>>> Just got my first Auto (Disco 2 TD5 - 2001 MY).
>>>
>>> On a slope I thought an Auto should not roll back when in 'D' but mine
>>> doesn't hold at all. Is this normal or is there a problem? The slope is
>>> reasonable but not too steep.
>>>
>>> Andy
>>
>> All autos seem to drive different. Some of mine would hold on a gentle
>> hill, feet off all pedals in D, some wouldn't. My '98 Rangie which I
>> think has virtually the same ZF 'box as your Disco will creep forward
>> on the level in drive, and will also hold on a gentle hill. The
>> downside to a vehicle that holds on a hill is it creeps forward on the
>> flat so you need to keep the brake on! So long as yours is driving and
>> changing smoothly, there's nothing to worry about.
>>
>> Alan C
>>
>
>Drives OK, just wondered if there was some sort of 'clutch' in an auto that
>could wear with age?
>
>
No - unless it is a DAF!!!!!!
All autos (except a DAF) exhibit "drag" when ticking over in D, to a
greater or lesser extent. There's nothing inherently guaranteeing that
you will hold on a hill. Just a case of whether the drag is sufficient
to balance gravity.
My V8 auto Defender will hold on a fair slope. Put it in low ratio 1st
gear and you have to be pretty hard on the brakes to hold it back, but I
have the tick-over set a bit fast as I run it on gas.
--
hugh
Reply to address is valid at the time of posting

On or around Thu, 29 Jun 2006 15:49:03 +0100, "Andy"
<[email protected]> enlightened us thusly:

>Just got my first Auto (Disco 2 TD5 - 2001 MY).
>
>On a slope I thought an Auto should not roll back when in 'D' but mine
>doesn't hold at all. Is this normal or is there a problem? The slope is
>reasonable but not too steep.

only with the engine running fast enough to get enough drag from the torque
converter. If it's at idle it shouldn't move, really, or only very slowly,
and on any noticeable slope it'll roll back. a few more revs will partly
engage the TC and hold it still. If you do that long enough, you'll
overheat the transmission, mind.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"'Tis a mad world, my masters" John Taylor (1580-1633) Western Voyage, 1

"Andy" <[email protected]> wrote in message
news:[email protected]...
> <[email protected]> wrote in message
> news:[email protected]...
> >
> > Andy wrote:
> >> Just got my first Auto (Disco 2 TD5 - 2001 MY).
> >>
> >> On a slope I thought an Auto should not roll back when in 'D' but mine
> >> doesn't hold at all. Is this normal or is there a problem? The slope is
> >> reasonable but not too steep.
> >>
> >> Andy
> >
> > All autos seem to drive different. Some of mine would hold on a gentle
> > hill, feet off all pedals in D, some wouldn't. My '98 Rangie which I
> > think has virtually the same ZF 'box as your Disco will creep forward
> > on the level in drive, and will also hold on a gentle hill. The
> > downside to a vehicle that holds on a hill is it creeps forward on the
> > flat so you need to keep the brake on! So long as yours is driving and
> > changing smoothly, there's nothing to worry about.
> >
> > Alan C
> >
>
> Drives OK, just wondered if there was some sort of 'clutch' in an auto
that
> could wear with age?

Yes, there is. On the ZF4HP22 box (both early and later electronically
controlled versions such as that in the Disco II), the "A" clutch (main
forward drive clutch, engaged in all forward gears) is the weak link.
Ironically, it's the smallest diameter clutch in the 'box, with the lowest
surface contact area as well. This clutch wears at an accelerated rate due
to main oil pressure leaking past the steel seals on the input shaft and
applying a pressure to the clutch whilst in P, N and R, causing it to slip
and wear. There are 7 wet-multiplate clutches in this box, A, B, C1, C, D, E
and F.
The life of the 'box can be optimised by never, ever revving the engine in P
or N. What you should do is put the transfer box in N and select D on the
main box, handbrake firmly on, if you need to do anything which involves
revving the engine for any length of time.
As for creeping or not, some will creep on the flat and not on, say, a 5%
slope, others will roll back slightly on the same slope. It's down to the
individual torque convertors and the clearances set within them when they
are built/rebuilt. Just because one vehicle may roll back and another night
not, doesn't indicate a fault in itself. If the oil on the gearbox dipstick
is clear translucent red then you've nothing to worry about. If the oil is
dirty or brown, check the bank balance!
Incidentally, the ZF4HP24 as used in the P38 4.6 has an "A" clutch that is
considerably larger in diameter with a correspondingly larger surface
contact area (and a much higher torque handling limit), but it isn't a
straight swap as the pump housing (and A clutch carrier) is 15mm longer,
adding 15mm to the overall length. There is still the issue with the input
shaft seals though.
Badger.

> Incidentally, the ZF4HP24 as used in the P38 4.6 has an "A" clutch that is
> considerably larger in diameter with a correspondingly larger surface
> contact area (and a much higher torque handling limit), but it isn't a
> straight swap as the pump housing (and A clutch carrier) is 15mm longer,
> adding 15mm to the overall length. There is still the issue with the input
> shaft seals though.
> Badger.

So apart from having to lengthen / shorten the propshafts are you saying the
ZF4HP24 fits the block without modification.


--
Andy

"Fuzzy" <[email protected]> wrote in message
news:[email protected]...
>
> > Incidentally, the ZF4HP24 as used in the P38 4.6 has an "A" clutch that
is
> > considerably larger in diameter with a correspondingly larger surface
> > contact area (and a much higher torque handling limit), but it isn't a
> > straight swap as the pump housing (and A clutch carrier) is 15mm longer,
> > adding 15mm to the overall length. There is still the issue with the
input
> > shaft seals though.
> > Badger.
>
> So apart from having to lengthen / shorten the propshafts are you saying
the
> ZF4HP24 fits the block without modification.

Physically, yes, it fits as long as you use the matching 4.6 torque
convertor and engine drive plates. There's still the issue of the "24" being
electronically controlled though, the way round that is to rebuild the "24"
internals into the main case of a "22". Not the quickest of tasks, but the
result is a super-heavy-duty box with the original hydromechanical control
and no electronics.
In my case (building one at the moment) I'll move the engine forward 15mm,
it's easier to lengthen the exhaust 15mm than it is to modify and balance
the props, and my engine sits 2" further back than std anyways.
Badger.

On or around Thu, 29 Jun 2006 22:57:50 +0100, "Badger"
<[email protected]> enlightened us thusly:

>
>Yes, there is. On the ZF4HP22 box (both early and later electronically
>controlled versions such as that in the Disco II), the "A" clutch (main
>forward drive clutch, engaged in all forward gears) is the weak link.
>Ironically, it's the smallest diameter clutch in the 'box, with the lowest
>surface contact area as well. This clutch wears at an accelerated rate due
>to main oil pressure leaking past the steel seals on the input shaft and
>applying a pressure to the clutch whilst in P, N and R, causing it to slip
>and wear. There are 7 wet-multiplate clutches in this box, A, B, C1, C, D, E
>and F.

Actual failure of the A clutch though, IME, takes under 100 miles from
"slipping slightly under high throttle conditions" to "no forward drive at
all under any conditions". You can still go in reverse, though, since
reverse doesn't use the A clutch.

>As for creeping or not, some will creep on the flat and not on, say, a 5%
>slope, others will roll back slightly on the same slope. It's down to the
>individual torque convertors and the clearances set within them when they
>are built/rebuilt. Just because one vehicle may roll back and another night
>not, doesn't indicate a fault in itself. If the oil on the gearbox dipstick
>is clear translucent red then you've nothing to worry about. If the oil is
>dirty or brown, check the bank balance!
>Incidentally, the ZF4HP24 as used in the P38 4.6 has an "A" clutch that is
>considerably larger in diameter with a correspondingly larger surface
>contact area (and a much higher torque handling limit), but it isn't a
>straight swap as the pump housing (and A clutch carrier) is 15mm longer,
>adding 15mm to the overall length. There is still the issue with the input
>shaft seals though.

pity. both points...

Mind, I've only had one A clutch fail and that was a well-used box that I
reckon had had a hard life before I got it.
--
Austin Shackles. www.ddol-las.net 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.

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Thu, 29 Jun 2006 22:57:50 +0100, "Badger"
> <[email protected]> enlightened us thusly:

> Actual failure of the A clutch though, IME, takes under 100 miles from
> "slipping slightly under high throttle conditions" to "no forward drive at
> all under any conditions". You can still go in reverse, though, since
> reverse doesn't use the A clutch.

By the time it starts to slip in forward drive at high throttle, the damage
is already done! Most of the lining is worn by that point.

> >As for creeping or not, some will creep on the flat and not on, say, a 5%
> >slope, others will roll back slightly on the same slope. It's down to the
> >individual torque convertors and the clearances set within them when they
> >are built/rebuilt. Just because one vehicle may roll back and another
night
> >not, doesn't indicate a fault in itself. If the oil on the gearbox
dipstick
> >is clear translucent red then you've nothing to worry about. If the oil
is
> >dirty or brown, check the bank balance!
> >Incidentally, the ZF4HP24 as used in the P38 4.6 has an "A" clutch that
is
> >considerably larger in diameter with a correspondingly larger surface
> >contact area (and a much higher torque handling limit), but it isn't a
> >straight swap as the pump housing (and A clutch carrier) is 15mm longer,
> >adding 15mm to the overall length. There is still the issue with the
input
> >shaft seals though.
>
> pity. both points...
>
> Mind, I've only had one A clutch fail and that was a well-used box that I
> reckon had had a hard life before I got it.

It's revving them in neutral or park that does the most damage Austin, to
the point that most american states have special procedures for smog-testing
any vehicle with a ZF4 transmission, due to their law-suit culture. Do a
quick google and you'll see more info.
Badger.

On or around Fri, 30 Jun 2006 19:36:15 +0100, "Badger"
<[email protected]> enlightened us thusly:

>Physically, yes, it fits as long as you use the matching 4.6 torque
>convertor and engine drive plates. There's still the issue of the "24" being
>electronically controlled though, the way round that is to rebuild the "24"
>internals into the main case of a "22". Not the quickest of tasks, but the
>result is a super-heavy-duty box with the original hydromechanical control
>and no electronics.
>In my case (building one at the moment) I'll move the engine forward 15mm,
>it's easier to lengthen the exhaust 15mm than it is to modify and balance
>the props, and my engine sits 2" further back than std anyways.

As a point of (at the moment, academic) interest, how much do you charge to
do that (the rebuild I mean) - while I'm a good mechanic, I've not done an
auto rebuild and I doubt it would pay me to acquire the necessary knowledge
for a one-off, if I needed to do one.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"It is a characteristic of the human mind to hate the man one has injured"
Tacitus (c.55 - c.117) Agricola, 45

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Fri, 30 Jun 2006 19:36:15 +0100, "Badger"
> <[email protected]> enlightened us thusly:
>
> >Physically, yes, it fits as long as you use the matching 4.6 torque
> >convertor and engine drive plates. There's still the issue of the "24"
being
> >electronically controlled though, the way round that is to rebuild the
"24"
> >internals into the main case of a "22". Not the quickest of tasks, but
the
> >result is a super-heavy-duty box with the original hydromechanical
control
> >and no electronics.
> >In my case (building one at the moment) I'll move the engine forward
15mm,
> >it's easier to lengthen the exhaust 15mm than it is to modify and balance
> >the props, and my engine sits 2" further back than std anyways.
>
> As a point of (at the moment, academic) interest, how much do you charge
to
> do that (the rebuild I mean) - while I'm a good mechanic, I've not done an
> auto rebuild and I doubt it would pay me to acquire the necessary
knowledge
> for a one-off, if I needed to do one.

The problem with rebuilding autoboxes is that if you replace every clutch
pack, every sealing ring, torque convertor etc etc then it becomes extremely
obvious that there are a lot of reconditioners out there that don't bother
replacing ALL the parts, they couldn't make a profit otherwise! The parts
alone to do a proper, full rebuild are around £400, and that doesn't include
any "hard" parts such as clutch hubs if they are found to be excessively
worn on the drive splines, they're alloy cast parts and the tangs of the
clutch plates can wear into them, or the torque convertor stator spigot
shaft. Labour would be another £180ish, making a total of roughly £580, but
that's an extremely comprehensive build Austin. There are other mods that
can be done, such as a modified sprag clutch assembly which eliminates the
potential for losing 1st, this being another relatively common failure point
on these boxes. That mod adds roughly another £90.
To go the route of the extra 15mm and get the heavy-duty "A" clutch, you
also need to factor in the extra expense of needing 2 gearboxes from which
to build 1, you need a 22 and a 24 to amass all the necessary parts, and of
course the relevant torque convertor and drive plate assembly.
Badger.

Andy wrote:
> Just got my first Auto (Disco 2 TD5 - 2001 MY).
>
> On a slope I thought an Auto should not roll back when in 'D' but
> mine doesn't hold at all. Is this normal or is there a problem? The
> slope is reasonable but not too steep.
>
> Andy

Mine wont hold on a steep hill, but the wifes Touareg did, it had hil control so i guess they wont as
standard?

Nige

On or around Sat, 1 Jul 2006 11:05:50 +0100, "Badger"
<[email protected]> enlightened us thusly:

>The problem with rebuilding autoboxes is that if you replace every clutch
>pack, every sealing ring, torque convertor etc etc then it becomes extremely
>obvious that there are a lot of reconditioners out there that don't bother
>replacing ALL the parts, they couldn't make a profit otherwise! The parts
>alone to do a proper, full rebuild are around £400, and that doesn't include
>any "hard" parts such as clutch hubs if they are found to be excessively
>worn on the drive splines, they're alloy cast parts and the tangs of the
>clutch plates can wear into them, or the torque convertor stator spigot
>shaft. Labour would be another £180ish, making a total of roughly £580, but
>that's an extremely comprehensive build Austin. There are other mods that
>can be done, such as a modified sprag clutch assembly which eliminates the
>potential for losing 1st, this being another relatively common failure point
>on these boxes. That mod adds roughly another £90.

Not silly money though, compared to some of the others in the market. I'd
rather part with 600+ notes for a proper rebuild than 400 notes and not
know.

>To go the route of the extra 15mm and get the heavy-duty "A" clutch, you
>also need to factor in the extra expense of needing 2 gearboxes from which
>to build 1, you need a 22 and a 24 to amass all the necessary parts, and of
>course the relevant torque convertor and drive plate assembly.

true... does the 22 have to be fully functional? Mind, I scrapped the blown
one I had here...
--
Austin Shackles. www.ddol-las.net my opinions are just that
"I am tired and sick of war. Its glory is all moonshine... War is hell"
Gen. Sherman (1820-1891) Attr. words in Address at Michigan Military
Academy, 19 June 1879.

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Sat, 1 Jul 2006 11:05:50 +0100, "Badger"
> <[email protected]> enlightened us thusly:
>
> >The problem with rebuilding autoboxes is that if you replace every clutch
> >pack, every sealing ring, torque convertor etc etc then it becomes
extremely
> >obvious that there are a lot of reconditioners out there that don't
bother
> >replacing ALL the parts, they couldn't make a profit otherwise! The parts
> >alone to do a proper, full rebuild are around £400, and that doesn't
include
> >any "hard" parts such as clutch hubs if they are found to be excessively
> >worn on the drive splines, they're alloy cast parts and the tangs of the
> >clutch plates can wear into them, or the torque convertor stator spigot
> >shaft. Labour would be another £180ish, making a total of roughly £580,
but
> >that's an extremely comprehensive build Austin. There are other mods that
> >can be done, such as a modified sprag clutch assembly which eliminates
the
> >potential for losing 1st, this being another relatively common failure
point
> >on these boxes. That mod adds roughly another £90.
>
> Not silly money though, compared to some of the others in the market. I'd
> rather part with 600+ notes for a proper rebuild than 400 notes and not
> know.
>
> >To go the route of the extra 15mm and get the heavy-duty "A" clutch, you
> >also need to factor in the extra expense of needing 2 gearboxes from
which
> >to build 1, you need a 22 and a 24 to amass all the necessary parts, and
of
> >course the relevant torque convertor and drive plate assembly.
>
> true... does the 22 have to be fully functional? Mind, I scrapped the
blown
> one I had here...

I can lay my hands on at least 3 blown 22's, they're not the hard ones to
get! More of an issue is how blown they are with respect to how much (if
any) contamination has got into the valve block itself, as that's a right
royal pain to strip. Never wears, just sticks with the contamination off the
burnt / broken friction linings. It's just too easy to get a machine-gun
effect of springs flying around the workshop if you remove the wrong bit in
the wrong order.!!
Many years ago I was just over £600 for a recon Ford A4LD (Mk3 granada) box,
one of the most disgustingly unreliable autoboxes ever made. I thought I was
getting a fully rebuilt box but after taking the car back to Leeds 3 times
(the firm that rebuilt it were in Leeds, it was easier to take the car to
them than spend the time removing and fitting the box constantly, let them
have the hassle!) I gave up and had it repaired properly by a firm in
Preston. Good guys in that Preston workshop, they showed me what was what, I
learnt a lot about autoboxes from them in only a few hours, but it was
enough to overcome any fears I had about touching them. The biggest issue is
finding someone who will sell you the parts, not the frictions they're easy
to get but the "hard" parts. ZF4 is an easy box to strip and rebuild.
Badger.