25th Feb 2011, 21:39
The transmission is supposed to do that. It's downshifting when you are braking and going downhill. Well, I don't know if it actually detects whether your car also at a downhill angle, but I have a Civic and it does this. I used to drive stick, and if you ask anyone else who also drives stick, this is a helpful thing to do. It provides engine braking by having the wheels turn the engine, just compressing air in the cylinders with minimal fuel (less than or equal to the amount injected in idle mode). This makes your brakes last longer and places you in the correct gear early for the impending slowdown. The car's computer adjusts to your driving style, and if you pay attention, it only does it when you are also braking, so that it's only when you intend to slow down.
I do not have any sources to cite for this as of yet, but I will post again when I have a chance to look at my manual. I'm pretty sure I also read it in there. If I find it, I'll tell you which page, otherwise you can look for it yourself.
17th Sep 2010, 12:00
With regards to the transmission issue, that is normal for Civics. Both my 2005 and 2009 have done that. I can guarantee that your transmission is not about to go, as it did that on my 2005 for the 4 years I had it, and the transmission still shifted like new by the end of my lease. Now if your Civic was a 2002, I might be worried, as the reviews suggest that 2002 was a bad year for Honda's transmissions.