Re: [Fwd: 5er automatic (tiptronic?)]

[andrew.j.thomas@xxxxxx]

Dear all,

Jim (j.cash@domain.elided) writes:

> Steptronic has been around for about 4 years (was on the E38's in
> Europe in 94).

Correct, Jim. And remember that the 'Steptronic' part of it is only the
control mechanism for the same old ZF five-speed autobox (i.e. the
mechanicals are the same, whether you have a Steptronic lever or the
regular P-R-N-D-4-3-2 gait).

That GM four-speed autobox was only fitted to 5ers destined for the US
market. Euro market cars all come with the ZF five-speed autobox (except
the new 530d six-pot diesel which uses - wait for it  - a FIVE-speed GM
autobox). To start with they fitted the non-Steptronic P-R-N-D-4-3-2 gait
to the 520i and 523i, but now the Steptronic control system comes included
whenever the autobox is specified.

As far as I know. the 6 and V8 5er autos in Europe all use the ZF
five-speed autobox in varying levels of max. torque capacity. Except that
new 530d diesel, which uses the new GM 5-speeder autobox, as I mentioned
above. The reason? Cheaper and lighter.

Now, this new diesel-bound GM five-speed autobox will also be fitted to
1999 E39 auto 5ers in the US. It will also appear in the 323i and 328i; in
other words, wherever the GM four-speeder auto appeared before, the GM
five-speeder will appear instead. Except in the E46 318i and 1.9 litre Z3,
where the four-speeder is retained should you specify automatic
transmission.

So from 1999 MY onward, Euro cars will retain the ZF five-speeder where US
cars have the GM five-speeder. No bad thing, for those of you with bad
memories of GM product, as GM knows how to make good, strong autoboxes.

I have absolutely no idea why this is such a stupidly complicated state of
affairs. I can understand why a simpler four-speeder 'box was originally
specified in the States (less need for longer gear ratios than certain
parts of Europe). But I have no idea why BMW chooses two suppliers of
five-speed auto transmission. ZF-equipped cars in my experience shift
harder and faster than the GM-equipped cars, which may have something to do
with it, although I would have thought the electronic control system looked
after shift speed, and that can be tweaked. Perhaps BMW is slowly switching
its auto supplier exclusively to GM, but still has an existing arrangement
with ZF (I know the top-spec ZF 'boxes handle more torque than the new GM
five-speeder in its current rating, but they're heavy and expensive).

Can anyone else offer an explanation?

Yours, confused,

Andrew T
'95 318is. GM 'box. No, four-speed ZF. Until 1994. Maybe. Or was that the
E30? I don't know. No, definitely a GM 'box. Silver ones had GM 'boxes.
Yes, that's right. And some red ones. As long as they where sold in the
South-East.

PS all the above is based on several reports from Autocar magazine over the
last few weeks.


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