i usually put it into D3 (below D) when its raining out but i dont really know what its real purpose is.
does anyone know what the D3 mode is meant for?

 

D3 limits the gears available to 1, 2 and 3. I'd just leave it in D, which allows 1, 2, 3, 4 and 5.

 

D3 wont' shift above 3rd gear. Use when driving around town and need more power/engine breaking and won't be travelling at high speeed.

 

It limits your car to the 1st 3 gears. It's useful for when you're towing something, going up a steep mountain, or using the engine to engine-brake down a mountain.

In some situations, like very steep mountains, you might even drop it down to D2.

For raining situations, you don't need D3.

 

Bad idea. VSA is what helps you in rainy/slick road conditions. Just curious, how fast do you do with it stuck in 3rd gear?? How often do you have to fuel up in winter?
Go directly to RTFM. Do not pass GO, do not collect $200.

Okay, enough snarking.

FWIW, I use D3 in campuses and school zones where the limit is 25 mph. It's not foolproof, but it discourages the car (5AT) from shifting into 4th and exceeding the limit on a downhill. I've embarrassed myself by absentmindedly leaving it in D3 after leaving a campus, and wonder why it's not accelerating to 45 so well. Gas guzzler me.
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BTW, mod: recommend move to general discussion, this isn't a problem or fix.

 

I only use D3 when I drive up steep roads or coming down steep roads. That should only be the time you should use it.

 

I think D3 is a left over from the good old days before SS mode. Back in the day, there only were 3AT and 4AT and most of them were pretty crappy. You would have to shift to D3 going up hills because the tranny wouldn't downshift and the engine would bog down. D3 was also used to pull heavy loads because D4 was just an overdrive gear and the engine didn’t have enough torque to maintain your speed in that gear. You would use D3 going down hills to slow down because you would accelerate to +80 mph with the crappy tranny when the speed limit was only 55 mph.

I found out D3 or SS in 3rd gear is the perfect gear for “spirited driving” on mountain switchbacks.

 

when I had my integra, i used D3 to engine brake as well as downshift.

 

i never use d3

 

if you keep your rpms up in D up a hill, then it'll never shift into 4th or 5th anyway. and i've noticed that these cars do a great (almost too good) job of engine breaking on their own going down hills. if i'm in 3rd and start going down a hill, it won't shift to 4th or especially 5th when i pick up a little speed. in fact, i don't pick up speed without hitting the gas on a downslope.

going up big hills, i usually just pop it over into SS instead of down to D3.

just my

 

Ever seen THE DRIVER (Walter Hill movie with Ryan O'Neal and (sigh) Isabelle Adjani)? Kinda comic bookish, but the driving scenes are considered some of the best of the 1970s. I think they portrayed The Driver (no name given) shifting from D to D1, D2, et al, for rather violent changes in traction and braking. Not something you'd do to your own car, I'd think.

It's worth the rental price just for the "audition" he performs with a Mercedes.

I've been QUITE impressed with the TSX's 5AT in that it doesn't downshift in a hurry when I accelerate quickly and keep the RPMs up, as you say. I don't have a broad experience with auto's (mostly drive manual), but I recall other even recent cars downshifting more readily. The TSX tranny is clearly tuned for performance and sportiness.

 

I kind of recall a thread where they said that the TSX (with AT) can sense the incline, and will either change the gear or do something when you're in SS mode. I'm not sure if I had understood it properly at the time (I drive a MT), but if it were correct, maybe D3 is the same as what you get when you go down a steep incline in SS mode?

 

^^^ yep it'll apply engine braking on a slope, or well, do its best to keep the speed at which you entered the decline given you lay off the gas pedal through your decent

 

I've found that the 5AT (in my 2006 model) will not change gears in SS mode, even when I'm holding the cruise control ACCEL button down. It only changes to downshift during braking, as per the manual. It does downshift to maintain speed on an uphill, naturally.

I have noticed that *sometimes* the system will brake (engine or braking, I dunno) when the cruise control is set for, say, 35mph and hit a downhill and start accelerating past that. But on some hills, it doesn't. I got caught in a speed trap Labor Day because it sped up on a downhill leading to a reduced speed limit zone. (Got it reduced, though, thank heavens/lawyers.)

 

I usually use it in snowy situations that way you don't hear up pass 3 when you're stuck and have to give it some gas

 

D3 is for overtaking cars or passing on a divided two lane highway. That's why it drops two gears.

 

I agree.!!