I used to use manual mode (or Tow/Haul mode) to catch the 2nd prime up shift,
Have since found out its BAD , and one of the weakest links in Dodge transmissions.
3G guys who race will tell you to avoid it at all cost if you want your trans to last.
I now just run 1-2-3, ET's are the same but my trap speed is down slightly now.
I'll bet I'll pick that back up with some more HP and headers next time out.
I track test the crap out of everything I do to my truck,
Have well over 200 passes in the last 2 years on her now.
and when the track is closed I use a back country road and my tuners
Here's an old vid, testing with my old BullyDog using 2nd prime
Quite a bit more power and shifting at 6400 rpm with a Diablo 93 tune now
Traction problems ...check out the 2nd gear chirp on this one