Is there a sensor on the Auto tranny models that detect uphill/downhill motion? - Honda Prelude Forum

PreludeNmphs · 06-27-2011, 07:56 PM

Ok, this may sound like a weird question if you haven't ever heard this about the auto trans models. When I first bought this car new in 2002, i noticed if I was going down a hill and just slightly touched the brakes it would downshift from 4th to 3rd. I talked to the dealer and they told me there was a motion sensor that controlled that downshift AND it would delay upshift from 3rd to 4th going uphill.

It had always worked exactly like this over the last 176k miles, but since I had the trans rebuilt at about 168k I guess I've really paid attention to suttle things about the trans. I was thinking maybe I need to just remove this sensor IF IT REALLY EXISTS.

If it does exist, does anyone know where?

indylude18 · 06-27-2011, 10:07 PM

Unlikely it exists at all. Automatics all suck on hills, that is the main reason why pretty much every car/truck/van/suv with an automatic transmission has the ability to manually select gears.

You should be in 2nd or 3rd gear while going up a steep hill for the extra torque, and also be in 2nd or 3rd gear going down a steep hill to engine brake to avoid overheating the brakes. Under neither circumstance should you really be in overdrive (4th) at all.

dblair · 06-28-2011, 01:26 PM

Honda called it "Grade Logic" and used it on several of their automatics.

PreludeNmphs · 07-01-2011, 09:10 PM

Quote:

Originally Posted by dblair

Honda called it "Grade Logic" and used it on several of their automatics.

yeah, that is something like they told me when I first noticed it just after I bought the car new. I've just accepted it all these years, but am thinking I'd like to bypass this crap if i knew what controlled it.

PreludeNmphs · 07-18-2011, 07:14 PM

Just thought I'd update this thread incase someone else starts looking for the answer for this odd behavior in the AT.
Honda Prelude -- Transmission - Honda.com

Interesting read. I'd love to "turn it off" and see how it shifts with the logic in place if anyone knows how. Just another reason I wish my baby had a 5sp.

usmcmarc · 07-18-2011, 09:55 PM

Yeah..Grade Logic. I sold Hondas from 1994-1997. We plugged that Grade Logic like it was the best things since sliced bread! LMAO

Other than Cruise Control on long trips...I hate cars that make decisions for you, I want to drive the car..not be driven.

That 01 BB6 · 07-22-2011, 08:21 PM

Um...is it really a big deal if your trans pops itself into 3rd going up a hill instead of staying in 4th? Not trying to be sarcastic at all, I just think it would help to be in 3rd anything instead of bogging uphill with non-existent torque. As far as downhill driving is concerned, pop it into triptronic or neutral.

Or work on getting parts together for a 5spd like myself.