320 -04 auto: no lock-up?

Doesn't the auto transmission have a lock-up feature
at all, or if yes, how does it work?

Even at 100km/h and 2000 rpm the engine spins up
in that characteristic way it does when there's
no lock-up.

Thanks,

--
Håkan

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In article >,
-= H.=- > wrote:
> Doesn't the auto transmission have a lock-up feature
> at all, or if yes, how does it work?

> Even at 100km/h and 2000 rpm the engine spins up
> in that characteristic way it does when there's
> no lock-up.

You can see it come in on the tach in my E39 - at about 60 mph on a light
throttle. However, transmission has to be in normal mode - not sport.

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Dave Plowman London SW
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"Dave Plowman (News)" > wrote in message
...
> In article >,
> -= H.=- > wrote:
> > Doesn't the auto transmission have a lock-up feature
> > at all, or if yes, how does it work?
>
> > Even at 100km/h and 2000 rpm the engine spins up
> > in that characteristic way it does when there's
> > no lock-up.
>
> You can see it come in on the tach in my E39 - at about 60 mph on a light
> throttle. However, transmission has to be in normal mode - not sport.

Should it lock at about the same on my 525i E34?
Must say it's not something I've particularly noticed.
Mike.

In article >,
Mike G > wrote:
> Should it lock at about the same on my 525i E34?
> Must say it's not something I've particularly noticed.

My E34 was a '92 with the first 5 speed ZF, and that felt just like a 6th
gear when it cut in - you could both hear it happen and *just* feel it
too, as well as seeing it on the rev counter.

Other thing was it's inhibited with a cold engine - dunno how exactly that
sensor works.

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Dave Plowman London SW
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"Dave Plowman (News)" > wrote in message
...
> In article >,
> Mike G > wrote:
> > Should it lock at about the same on my 525i E34?
> > Must say it's not something I've particularly noticed.
>
> My E34 was a '92 with the first 5 speed ZF, and that felt just like a 6th
> gear when it cut in - you could both hear it happen and *just* feel it
> too, as well as seeing it on the rev counter.
>
> Other thing was it's inhibited with a cold engine - dunno how exactly that
> sensor works.

Mines a '94. Presumably the same box.
I've noticed on a light throttle, the revs can drop to around 1500 plus, yet
I'm still doing 55-60mph, with 35-40 mpg on the 'gasometer' thingy :-)
There doesn't appear to be any noticeable 'step' though when it does that.
It just seems to ease into it, and the rev counter still shows an increase
if I give it just the slightest more throttle.

Maybe I'm imagining it, but the colder it gets, the longer it seems to hang
onto the gears first thing in the morning.
Maybe the ECU has a temperature sensor, or it's just down to the oil being
thicker.
Mike.

On Thu, 23 Dec 2004 17:56:46 +0000, Mike G wrote:

>
> "Dave Plowman (News)" > wrote in message
> ...
>> In article >,
>> Mike G > wrote:
>> > Should it lock at about the same on my 525i E34? Must say it's not
>> > something I've particularly noticed.
>>
>> My E34 was a '92 with the first 5 speed ZF, and that felt just like a
>> 6th gear when it cut in - you could both hear it happen and *just* feel
>> it too, as well as seeing it on the rev counter.
>>
>> Other thing was it's inhibited with a cold engine - dunno how exactly
>> that sensor works.
>
> Mines a '94. Presumably the same box. I've noticed on a light throttle,
> the revs can drop to around 1500 plus, yet I'm still doing 55-60mph, with
> 35-40 mpg on the 'gasometer' thingy :-) There doesn't appear to be any
> noticeable 'step' though when it does that. It just seems to ease into it,
> and the rev counter still shows an increase if I give it just the
> slightest more throttle.
>
I think that's the torque coverter in action. I don't know what rpm it
locks up at, but on my 01 525 it is noticable when the rpm is lower than
about 2500rpm. Crusing at highway speed and backing on the throttle I'll
see a few hundred rpm drop w/o any noticable deceleration. On my car that
effect disappears above 3000rpm. Backing off the throttle there results in
noticable deceleration.

> Maybe I'm imagining it, but the colder it gets, the longer it seems to
> hang onto the gears first thing in the morning. Maybe the ECU has a
> temperature sensor, or it's just down to the oil being thicker. Mike.

I think this may be by design. Holding off shift points on cold engine
results in a higher volume of hot gas through the cats. That helps to get
them up to temperature and working sooner.

--
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Thanks for the response.

I hope I can sort this out in English.

When I compare the behavior of the 320 with the
auto transmission in my Audi V6 the difference is
significant. In the Audi the ATM locks up on the
3rd and 4th gear almost as son as you are easy on
the throttle. You feel when the clutch locks
the gear and you have to kick-down to set off for
overtaking etc. In the 320, by contrast, I don't
feel any lock-up at all - at any speed - and when I
hit the throttle driving at 100km/h (60mph) the
engine answers immediately by spinning - just like
the typical un-locked behavior. Again, very different
to the Audi V6 which virtually behaves like manually
geared car in locked state.

I might add that the 320 consumes as much gas as
the 2.8 litre Audi V6 engine, so the more conservative
operating mode of the Audi box pays off.

Very strange. (And no, the BMW is not sport mode)

--
Håkan

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In article >,
-= H.=- > wrote:
> I hope I can sort this out in English.

> When I compare the behavior of the 320 with the
> auto transmission in my Audi V6 the difference is
> significant. In the Audi the ATM locks up on the
> 3rd and 4th gear almost as son as you are easy on
> the throttle. You feel when the clutch locks
> the gear and you have to kick-down to set off for
> overtaking etc.

I'm not sure about your version, but on mine the TC only locks in 5th. And
will drop out of lock without using kickdown. Nor does it need kickdown to
drop a gear either at these sort of speeds.

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Dave Plowman London SW
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"-= H.=-" > wrote in message
...
> Doesn't the auto transmission have a lock-up feature
> at all, or if yes, how does it work?
>
> Even at 100km/h and 2000 rpm the engine spins up
> in that characteristic way it does when there's
> no lock-up.
>
As far as I am aware, the latest generation of GM boxes used by BMW don't
have a traditional lock-up as, say, the ZF boxes. The ZF (and plenty of
others) have a clutch plate within the torque converter and this is either
engaged or disengaged with no variable. The latest GM boxes appear to use
variable angle stator vane packs within the torque converter to achieve the
same effective result by eliminating "slip" hydraulically rather than
mechanically to get round the clutch wear problems. This is then controlled
by the gearbox ecu, dependant on speed, load, fluid temp, engine temp etc
etc.
Badger.