Plastic sleeve on shift linkage cable is broken

Sounds like a broken Shift Cable or Linkage. Check the Transmission where the Shift lever is attached to the cable or linkage.

Could be the shift cable is dry for oil due to the age. You may have to replace it. You could disconnect the linkage at the trans and try it to confirm.

SOUNDS LIKE A CABLE/ SHIFT LINKAGE ISSUE, FOLLOW IT OUT THE FIREWALL AND DOWN TO THE TRANS, GET SOMEONE TO HELP AND WATCH IT MOVE, CABLE COULD BE SIEZED.

I take it that you have a standard transmission ? there is no adjustment, but on the saturns the plastic insert on the shifter lever (remove the center console) is what breaks, Napa auto parts has the replacement part for about $20, or you can go to saturn and spend $200 on replacing both cables

what is stuck?

the linkage or the cable from the shifter to the trans.?

block the tires so the car can not roll away...
open the hood and remove the cable from the shifter on the transmission.
see if you can manualy move the shifter on the trans.
if that moves... you may need to replace the cable (shift linkage)

The shifter pawl on the trans maybe stuck in between gears from a broken spring? On it but try to remove the neutral safety switch to see if that is frozen it could've become broken and jammed from force applied trying to get the shifter to work and the shift lever will not move also disconnect the linkage and try to shift it from the trans with the neutral safety switch out and try to move the shifter cable it could be frozen or if any work was done the cable could be crimped inside the sheath causing it to not travel freely if it's frozen use a torch on the metal wire part only and gradually heat it and try to move it you must understand that I'm not there so you have to investigate the possibility of all described here yourself to get to the problem I don't think it's internal failure from your description so external investigation will be a big help especially if you have driven in deep snow or a lot of slush good luck stephen

If it is an Automatic, there is only one cable that goes to the transmission. If it is a manual, there should be two. You will have to disconnect the cable from under the hood, and see if the levers are loose there. If they are, it might be as simple as tightening them back down. If not, the trans may need a rebuild.

Have someone look @ linkage on trans. while someone moves shift lever thru the gears. If lever @ trans doesn't move then its in the linkage between the column and trans. (possible clip or pin broken @ linkage jounts). If lever @ trans moves then its a trans. internal prob.

Sounds like the shifter cable,if it is and automatic trans. has broken. look at the trans selector under the truck and see if it moves when you select different gears.If it doesn't its the cable

the shift interlock has malfunctioned....here is a way to get it to the dealer without having to have it towed. remove the shroud around the shifter assembly...there are 2 screws at the front of it you will need to remove. once you have the shround removed you will see 2 cables the one closest the drivers side is theinterlock cable. start the vehicle hold your foot on the brake... now follow the cable back til you find where it connects...push where it connects rearward as you shift the vehicle into gear...