I have 88 trooper will shift up and down manually but not on its own any suggestion. pulls great[img]smileys/smiley19.gif[/img]

check the kickdown cable near the throttle cable,possibly frozen or broken inside the housing.this cable causes the throttle valve to move inside the transmission.if its not moving the trans will not know when to upshift.with speed an throttle position.the cable connects at the bottom of the t-body an the other end at the trans.also make sure its in adj.you may havae to find a good service manual for this procedure.