E30 Zone

never had a BMW auto but I would suspect you can select 1,2,or 3 with the shift lever manually.

By moving the switch to "321" I am guessing it just means the gearbox will only select those gears when the shift lever is in D. i.e. it won't go into 4th gear when the switch is in "321" position?

anyone, bueller.....................

positions 3, 2 and 1 are the 'towing gears'. You should be able to select either 1, 2 or 3. (going on my mates 316 auto and how his box works)

Its like downshifting in a gay not really a downshift automatic way.

edit> just re-read your post, no idea what the switch is for, I thought you meant gear lever positions...

Probably, as has been said, means it will only select those three in D.

321, is a dusty bin thing right??

Or a Thunderbirds count down??

Actually as Munky said, also to be used for controlling downhill decents so you're not on your brakes permanently.

321 means you can put the selector level in 1 or 2 or 3 and the car will stay in that gear, it sort of makes the car manual as you can force it to shift, but note it will not downshift when you want as the gearbox / management computer will not let it over rev, and if you really hit the rev limiter it will also shift up.

Economy uses all the gears

and sport will rev higher before upshifting and will not go into overdrive

also particually usefull in traffic when the auto wants to shift up but your only crawling so theres no point.

And if you have the lever in position 'D', then it will stay in third.

What you have is an EH Switchable box also fitted to Sport autos.

E is for everyday driving and works like any other auto, it uses all the gears and goes in to overdrive/lockup for economy at just over 50mph (depending on what diff you have). You can use kick-down for overtaking or move the gear lever down to 3rd, or even 2nd.

S is sport mode and as already described it holds the gears and changes up at higher revs. It only uses gears 1 to 3 and won't change up into 4th. You can also change manually in this mode and hold the gears to even higher revs so you have more control if you're pushing hard. You can also change down and you get engine breaking just like a manual which also gives more control for hard cornering etc and also to be in the right gear on the exit of corners/bends.

3-2-1. This primarily desined to give control in difficult 'traction' conditions like snow and mud so that you can pull away in 3rd when low revs are needed. Not advisable to use this mode in everyday conditions or long periods as it will 'boil' the box!