ZF 4-speed auto .... problem?

This is either simple or expensive. My '85 RR with 4-speed ZF auto box
seems to lock up its torque converter a tad early. The gear changes from a
standing start are all there and nicely smooth but the converter locks up at
a fraction over 40mph (and unlocks at about the same on the way down). I
had another RR with a ZF auto some years ago which used to lock at around
50-52mph on the way up and unlock at around 49mph on the way down. I also
seem to recall from somewhere that the 50-52mph lock was about right and it
also felt about right - meaning that the current situation isn't. Locking
up at 40 puts the rpm down to about 1500 which seems way off the power band
for the V-8 (3.5 EFi) and, unless I'm just tootling up to the cruise, I have
to kick down for any sensible acceleration (when wanting to overtake for
example) or knock it back and hold 3rd on the shifter.

So, it changes up and down ok (although the changes seem somewhat
"compressed", if you know what I mean), the kick-down works fine (and it
will hold in a lower gear quite convincingly) and there are no leaks
whistles or wheezes from the box. Has anyone any ideas about how to bring
the converter lock into the usual place in the speed/rpm zone. Haynes, as
usual, is particularly vague (like, blank) on this problem.

TIA,
Steve

"Steve" <[email protected]> wrote in message
news:[email protected]...
> This is either simple or expensive. My '85 RR with 4-speed ZF auto box
> seems to lock up its torque converter a tad early. The gear changes from
a
> standing start are all there and nicely smooth but the converter locks up
at
> a fraction over 40mph (and unlocks at about the same on the way down). I
> had another RR with a ZF auto some years ago which used to lock at around
> 50-52mph on the way up and unlock at around 49mph on the way down. I also
> seem to recall from somewhere that the 50-52mph lock was about right and
it
> also felt about right - meaning that the current situation isn't. Locking
> up at 40 puts the rpm down to about 1500 which seems way off the power
band
> for the V-8 (3.5 EFi) and, unless I'm just tootling up to the cruise, I
have
> to kick down for any sensible acceleration (when wanting to overtake for
> example) or knock it back and hold 3rd on the shifter.
>
> So, it changes up and down ok (although the changes seem somewhat
> "compressed", if you know what I mean), the kick-down works fine (and it
> will hold in a lower gear quite convincingly) and there are no leaks
> whistles or wheezes from the box. Has anyone any ideas about how to bring
> the converter lock into the usual place in the speed/rpm zone. Haynes, as
> usual, is particularly vague (like, blank) on this problem.
>
> TIA,
> Steve

Hello Steve
As far as I know any changes to the ZF have to be made internaly i.e.
hydraulic adjustments with gearbox out of the vehicle.
I have had a number of diesel auto Discovery's with various lock-up speeds M
reg.Tdi300 was 48mph very nice setting, S reg. SafariTdi300 was 52mph over
the 50mph speed limits having to listen to the torque converting making the
noise and wasting fuel. The Td5 was no better about 53mph again far too
high.
I wish all my Disco's had locked up well below 50mph I would have been very
happy.
Gordon
>

My RR 3.5efi auto locks up at about 42mph if you need a quick getaway as you
say kick it down Paul
"Steve" <[email protected]> wrote in message
news:[email protected]...
> This is either simple or expensive. My '85 RR with 4-speed ZF auto box
> seems to lock up its torque converter a tad early. The gear changes from
a
> standing start are all there and nicely smooth but the converter locks up
at
> a fraction over 40mph (and unlocks at about the same on the way down). I
> had another RR with a ZF auto some years ago which used to lock at around
> 50-52mph on the way up and unlock at around 49mph on the way down. I also
> seem to recall from somewhere that the 50-52mph lock was about right and
it
> also felt about right - meaning that the current situation isn't. Locking
> up at 40 puts the rpm down to about 1500 which seems way off the power
band
> for the V-8 (3.5 EFi) and, unless I'm just tootling up to the cruise, I
have
> to kick down for any sensible acceleration (when wanting to overtake for
> example) or knock it back and hold 3rd on the shifter.
>
> So, it changes up and down ok (although the changes seem somewhat
> "compressed", if you know what I mean), the kick-down works fine (and it
> will hold in a lower gear quite convincingly) and there are no leaks
> whistles or wheezes from the box. Has anyone any ideas about how to bring
> the converter lock into the usual place in the speed/rpm zone. Haynes, as
> usual, is particularly vague (like, blank) on this problem.
>
> TIA,
> Steve
>
>

On or around Tue, 7 Dec 2004 18:52:33 +0000 (UTC), "Steve"
<[email protected]> enlightened us thusly:

>This is either simple or expensive. My '85 RR with 4-speed ZF auto box
>seems to lock up its torque converter a tad early. The gear changes from a
>standing start are all there and nicely smooth but the converter locks up at
>a fraction over 40mph

has it always done this?

They're not all set the same. ISTR one or another variant being set to lock
up early. Is it the original box for the vehicle?

52 - ish or as near as I can tell with the speedo needle waving around!
But also 2200-ish rpm before lockup to about 1900-ish after IIRC. All
in a 1988 RRC

However, my workshop manual says - in test 10 - that the direct drive
clutch will only engage if 4th gear is engaged at 40 to 44 mph.
Disengagement occurs at 39 to 42 mph. This suggests that mine locks up late

I have a scan of the page from the manual showing the shift pattern if
that's of any interest. Other than that the manual only seems to
mention setting the kickdown cable.

Richard

--
Real email address is RJS at BIGFOOT dot COM

The information contained in this post
may not be published in, or used by

http://www.diyprojects.info

In <[email protected]> Steve wrote:
> This is either simple or expensive. My '85 RR with 4-speed ZF auto
> box seems to lock up its torque converter a tad early. The gear
> changes from a standing start are all there and nicely smooth but the
> converter locks up at a fraction over 40mph (and unlocks at about the
> same on the way down). I had another RR with a ZF auto some years ago
> which used to lock at around 50-52mph on the way up and unlock at
> around 49mph on the way down. I also seem to recall from somewhere
> that the 50-52mph lock was about right and it also felt about right -
> meaning that the current situation isn't. Locking up at 40 puts the
> rpm down to about 1500 which seems way off the power band for the V-8 (
> 3.5 EFi) and, unless I'm just tootling up to the cruise, I have to
> kick down for any sensible acceleration (when wanting to overtake for
> example) or knock it back and hold 3rd on the shifter.
>
> So, it changes up and down ok (although the changes seem somewhat
> "compressed", if you know what I mean), the kick-down works fine (and
> it will hold in a lower gear quite convincingly) and there are no
> leaks whistles or wheezes from the box. Has anyone any ideas about
> how to bring the converter lock into the usual place in the speed/rpm
> zone. Haynes, as usual, is particularly vague (like, blank) on this
> problem.

The first question has got to be - does it tend to stick in 1st gear
when it's cold ?

The second question is, have you checked the oil level correctly ? (low
oil often causes an early lock up)
Before checking the oil level you need to cycle the box (while cold)
through drive and reverse a few times then put it in neutral while you
check the oil. (don't forget the handbrake !)

The lock up is caused by a number of things but primarily by the
governor at the back of the box. The governor consists of a weight and a
spring connected to a valve that spins on the output shaft of the
gearbox. As the speed increases the centrifugal force opens the valve,
eventually, in conjunction with the hysteresis valve, it will cause the
box to lock up. The torque convertor also has an input on all of this
too but IME it's unusual for the TC to cause this sort of problem.

One thing to note is that all this happens before the transfer box which
should be an LT230 at that age. You should check that the transfer box
is actually a 1.222 ratio box rather than a 1.4 as a 1.4 (or 1.6) would
cause the box to lock up at a slower road speed if you are on standard (
205/16) tyres. The RPM you mention does sound right for a 1.222 though.

You can also try adjusting the kick down cable as it's not unknown for
these to be badly adjusted making the vehicle less responsive. The kick
down cable effects the gearbox throughout it's operation and, if badly
adjusted, it can cause the gearbox to lock up when it shouldn't. It can
also effect the shift pattern and timing. If the gearbox hasn't been
apart since it left the factory and the crimp on the end of the
kickdown cable hasn't moved then the crimp should be about 1/8 of an
inch from the cable outer with no throttle. If the gearbox has been
apart/repaired or the kickdown cable replaced then there is a good
chance that the little crimp is meaningless. That being the case try
tightening the cable up a little at a time and see if that helps.

cheers

Dave W.
http://www.yorkshireoffroadclub.net/

"Austin Shackles" <[email protected]> wrote in message
news:[email protected]...
> On or around Tue, 7 Dec 2004 18:52:33 +0000 (UTC), "Steve"
> <[email protected]> enlightened us thusly:
>
> >This is either simple or expensive. My '85 RR with 4-speed ZF auto box
> >seems to lock up its torque converter a tad early. The gear changes from
a
> >standing start are all there and nicely smooth but the converter locks up
at
> >a fraction over 40mph
>
> has it always done this?
>

Since I've had it, yes.

> They're not all set the same. ISTR one or another variant being set to
lock
> up early. Is it the original box for the vehicle?
>

I've no idea if it's the original box. Lack of leaks clonks whizzes and
pings might suggest not, but then the speedo has only got 52k on it so
perhaps it is. The speedo could be a new one too though, who knows! Maybe
there's an OE serial number list that will match the box to chassis as it
left the factory.

As someone else has pointed out, their ZF-4 locks at the same point as mine,
so maybe there's nothing wrong after all .... which is why I put the
question mark in the subject line. I suppose having it lock at 40ish saves
it hunting when I get stuck behind the 45-53-45-53... (etc) mph Rover 412
(formerly Austin Montego ... inevitably green) road block. Now I just have
to worry about the blue-rinse in a Nissan Micra doing 35-43-35-43......
grrrrr!

By the way Austin, the gas is sorted now (RR goes BANG! ... if you
remember), thanks to someone on uk.r.c.f.lpg who sent me a scan of the
installation and setting manual. It's easy when you know how!

Steve

"Gordoni" <[email protected]> wrote in message
news:[email protected]...
>
> "Steve" <[email protected]> wrote in message
> news:[email protected]...
> > This is either simple or expensive. My '85 RR with 4-speed ZF auto box
> > seems to lock up its torque converter a tad early.
>
> Hello Steve
> As far as I know any changes to the ZF have to be made internaly i.e.
> hydraulic adjustments with gearbox out of the vehicle.

Maybe that's why Haynes is quiet on the subject then. I guess I just need
to live with it and enjoy the un-stressed burble.

Steve

"Richard" <[email protected]> wrote in message
news:[email protected]...
> 52 - ish or as near as I can tell with the speedo needle waving around!
> But also 2200-ish rpm before lockup to about 1900-ish after IIRC. All
> in a 1988 RRC
>

My previous RR was an '88 and locked at the same point as yours does - which
was why I wondered if this one had a problem. As an aside, changing from
4th to 5th in my Disco (manual box, obviously) has about the same RPM change
at about the same speed as your ZF ..... as indeed does the Series III with
standard SIII box + overdrive but running RR diffs.

> However, my workshop manual says - in test 10 - that the direct drive
> clutch will only engage if 4th gear is engaged at 40 to 44 mph.
> Disengagement occurs at 39 to 42 mph. This suggests that mine locks up
late
>

If your workshop manual is correct then my current ZF box is about right on
the money. Perhaps the later ones (somewhere between '85 and '88) changed
their lock points but your manual isn't amended or pre-dates the change.

> I have a scan of the page from the manual showing the shift pattern if
> that's of any interest. Other than that the manual only seems to
> mention setting the kickdown cable.

That's all I could find in Haynes too.

Steve

"Dave White" <[email protected]> wrote in message
news:[email protected]...
> In <[email protected]> Steve wrote:
> > This is either simple or expensive. My '85 RR with 4-speed ZF auto
> > box seems to lock up its torque converter a tad early. The gear
> > changes from a standing start are all there and nicely smooth but the
> > converter locks up at a fraction over 40mph (and unlocks at about the
> > same on the way down). I had another RR with a ZF auto some years ago
> > which used to lock at around 50-52mph on the way up and unlock at
> > around 49mph on the way down. I also seem to recall from somewhere
> > that the 50-52mph lock was about right and it also felt about right -
> > meaning that the current situation isn't. Locking up at 40 puts the
> > rpm down to about 1500 which seems way off the power band for the V-8 (
> > 3.5 EFi) and, unless I'm just tootling up to the cruise, I have to
> > kick down for any sensible acceleration (when wanting to overtake for
> > example) or knock it back and hold 3rd on the shifter.
> >
>
> The first question has got to be - does it tend to stick in 1st gear
> when it's cold ?

Not that I've noticed. It quite readily and smoothly goes up through the
gears, even when cold. The only thing I've noticed (and this only happened
once, last week during the "cold snap") was the shifter was stiff (ish) the
first time I went from P to D in the morning. It only did it that once and
on thinking "that was odd" and giving it a waggle up and down through the
range I couldn't replicate it.

>
> The second question is, have you checked the oil level correctly ? (low
> oil often causes an early lock up)
> Before checking the oil level you need to cycle the box (while cold)
> through drive and reverse a few times then put it in neutral while you
> check the oil. (don't forget the handbrake !)

Checked, just a gnats whang below full - and it's pink (the oil, not the
gnats whang ... although that might be pink too .... possibly ..... errr
.....)

>
> The lock up is caused by a number of things but primarily by the
> governor at the back of the box. The governor consists of a weight and a
> spring connected to a valve that spins on the output shaft of the
> gearbox. As the speed increases the centrifugal force opens the valve,
> eventually, in conjunction with the hysteresis valve, it will cause the
> box to lock up. The torque convertor also has an input on all of this
> too but IME it's unusual for the TC to cause this sort of problem.
>
> One thing to note is that all this happens before the transfer box which
> should be an LT230 at that age. You should check that the transfer box
> is actually a 1.222 ratio box rather than a 1.4 as a 1.4 (or 1.6) would
> cause the box to lock up at a slower road speed if you are on standard (
> 205/16) tyres. The RPM you mention does sound right for a 1.222 though.
>

Tyres are 205's. I'll check the TX box, hopefully the sticker is still on
there.

> You can also try adjusting the kick down cable as it's not unknown for
> these to be badly adjusted making the vehicle less responsive. The kick
> down cable effects the gearbox throughout it's operation and, if badly
> adjusted, it can cause the gearbox to lock up when it shouldn't. It can
> also effect the shift pattern and timing. If the gearbox hasn't been
> apart since it left the factory and the crimp on the end of the
> kickdown cable hasn't moved then the crimp should be about 1/8 of an
> inch from the cable outer with no throttle. If the gearbox has been
> apart/repaired or the kickdown cable replaced then there is a good
> chance that the little crimp is meaningless. That being the case try
> tightening the cable up a little at a time and see if that helps.
>

I'll bear this in mind and have a peep at the cable whilst I've got the
thing up in the air to look at the TX box ratio. Thanks for the help.

Steve

"Richard" <[email protected]> wrote in message
news:[email protected]...
> However, my workshop manual says - in test 10 - that the direct drive
> clutch will only engage if 4th gear is engaged at 40 to 44 mph.
> Disengagement occurs at 39 to 42 mph. >


These are the speeds my 86 RR locked up at. If hunting between gears bothers
you on uphill stretches then it is good practice to pull the lever back to
lock top gear out.

Huw