1988 F150, 5.0, C6 auto. Has a harsh shift from 1-2. The vac modulator holds vacuum fine (all the way from the top of the vacuum line at the engine), shifts 2-3 fine. Should I adjust the band and see if that helps, or just leave that alone? Truck has 120k miles, adjustment has likely never been touched before. Just did a fluid change on the trans last week, as well.

Thanks,
-Michael