98 1500 2 wd automatic 5.2 ltr will not move in reverse

check trans. fluid level of coarse , the solenoid control may be effecting this symptom but then you would not shift through all forward gears as normal, so now would assume its droping the transmission pan and check and adjust the reverse band, the reverse band strut may have fallen out from behind the reverse band. and in the pan.set in place and loosen lock nut on band adjusting bolt tighten bolt to snug and back off 2 1/2 turns and lock nut at that point