I hadn't really noticed this before, but after 4 months of owership when in SS mode in 4th and slowly going up a hill, it shifts down to 3rd automatically. I previously thought it stayed in the selected gear until automatically down-shifting to 1st when coming to a stop. Do your cars also experience a 4th to 3rd down shifts?

 

That is weird, I don't think it is supposed to do that. When in SS mode, it is supposed to stay in the selected gear unless you are coming to a stop. By any chance, were you trying to go uphill at 15 mph? That might have something to do with it.

 

The tranny senses things like the grade of the hill, the throttle position, engine rpms, etc and will try to hold the selected gear. If it determines that you would be better off in a lower gear, it will downshift so you don't get bogged down.

If you are going downhill, the tranny will downshift to engine-brake and theoretically reduce the load on the brakes. This happens at predefined speeds for each gear and isn't quite as variable.

 

It's normal on TL.
It automatically up & down shift when it's necessary. Just like when we started on 1st gear & automatically goes to 2nd. I know BMW is all manual.

 

I get the 2-1 auto downshift in SS mode alot. That pisses me off.

 

The speed is not all that slow - I was doing 35 mph (at about 1500 rpm) in 4th and it shifted down to 3rd on me. I think it might have something to do with the 'grade logic' like TLinBama suggested however, as it seems to keep happening at about the same spot on the hill just before I reach the crest which is a little anoying. I do like how it downshifts (in auto mode) when going down a hill and you apply the brakes.

 

Even in SS, if you are going up hill, and you are in too high a gear, the tranny DOES downshift.....I think it's listed in the manual some where... :p

It's on Pg 184 and 185 on Canadian Manual(I think US gets the same manual)....

Andy Kuo

 

SS mode will automatically downshift to prevent you from lugging. I've noticed that the SS computer will downshift if your RPM goes below about 800 and is steadily decreasing.

I've gotten used to the 1-2 shifting. I think of gears 1-2 as a single gear most of the time.

 

I sorta noticed this effect too, albeit in a roundabout way--I was cruising in (indicated) D5 at 65 mph or so on a slight downhill (not really steep, just enough that only truckers should gear down). Anyways, I flicked over to SS and noticed that the display indicated "4". Guess this proves that the tranny does have logic and apply the correct gear when needed, although IMO I don't think that a downshift to 4th was needed since the grade wasn't steep enough to justify a downshift so that speed could be reduced via engine braking. Also sorta a waste of fuel economy since now the car was going downhill on a lower gear even though it wasn't really needed.

Tony