When I bought my car in early 2010, I did a lot of routine fluid changes, just so I could know that I switched everything with a fresh start. Specifically with tranny, I used the Honda MTF from the dealer...seemed exactly the same as before. And by the way, 1st to 2nd is the "notchiest" of all my gears as well...hot or cold...
anyway, this spring, I put in Royal Purple...I can honestly say it does shift smoother, and help out the notchiness. However, it is still not smooth as going from 2nd to 3rd, or so one up the line.
Warmer does seem to help a bit, but the biggest thing I sometimes catch myself is not always depressing cluth all the way to floor...I mean its just a hair above. I've tried the test many times, and fully to the floor makes it so much easier than even a fraction above...and sometimes while you are driving , talking, etc, you shift and get a bit lazy and find you are not all the way down and sure enough, its notchy. It seems like 1st to 2nd is where this is noticed the most....
Maybe just my car??
Anyway, the gears are so tight, that it seems notchy...but I like that better than sloppy...
There is no doubt though that driving on the highway for a while and then shifting in the lower gears is smoother than strictly city driving in the lower gears...
So, that would add credibility to the "warm" aspecgt you have discussed
