i have the same vehicle.cant stand these trannys.
yours is an overdrive.is it column or floor shift??
there are 2 cables to the tranny. 1 is the shift cable & the other is a throttle valve-kickdown cable.
find the cable that goes thru the firewall.
disconnect it at the tranny end.it should shift easily in all positions. if not either the cable or the shifter itselt is binding up.
if the cable moves easily then you know that you have an internal problem in the trans which is the most likely problem on these trusty transmissions.