Rough shifts from 1st to 2nd
I've got an '06 3.0 auto ext. cab and for the past month it's been shifting roughly from first to second. It's got a 6in lift, 33s, 4.56 gears and an LS. When I baby it during shifts it's smooth but otherwise it's rough. I'm not sure if my foot has gotten heavy on the gas pedal. Or if the tranny fluid should be changed. I've checked the tranny fluid level and it's at the proper level on the dipstick. I did skip my 15k maintence (I'm currently at 20k+) but will get that done this Saturday. I'm not sure why it's shifting rough. Any responses will be helpful. Thanks in advance.
2006 XLT 2WD 3.0L Ranger aka Leech
Engine \ Performance: MagnaFlow custom cat-back exhaust; AFE Stage-1 intake - - Audio: Pioneer DEH-P5900iB with iPod adapter; Pioneer TS-A6881R 6x8s; Infinity BassLink II self-powered sub with expansion module - - Near-near future mods: SecondSkin damplifier; Pioneer Bluetooth adapter - - Near future mods: JBA headers; Underdog pulley \ belt combo kit; Rogue X Calibrator 2; Rogue 1.7:1 roller rockers