CK,
The line indicating what gear your in is the least of your worries. As the other posters have mentioned it could be a few different things happening. The experience I've had with shift levers in my two cars was always good, they worked without a problem.
A couple of things you can check is the shifter Knob. Check to see that the button your pressing ( to release the shiftlever ) moves and is working. Remove the shift knob and look in the hole to make sure the plunger inside moves. SOmetimes a plastic spring clip inside breaks. Try oiling the skift knob button
Typical mounting is a C - clip that faces the dash. The Clip can be pulled out with needle nose pliers or a small screwdriver.
Also after you get the knob off the shaft there maybe a plastic rod sticking out of the end of the shaft. The plastic rod gets pressed down by the plunger that is inside the Knob.
Check to see if you can push the plastic rod down, this is what unlocks the lever so it can be shifted into the variuos gears. Try running oil inside the shift lever ( its hollow ).
Pull up on the plastic rod, if its broken it may slide out and this could be part of the problem. If there is not enough rod sticking up you can push it down with a screwriver to see if you can release the shiftlever.
Maybe some of the shift linkage underneath the car is bend or loose.
I'm not sure if your car has the vinyl boot around the shift lever or not?
I'm not sure if your console uses a sliding track system ( my cars did ) within itself to indicate the gear your in, but if those plastic parts have cracked or the guides channels have cracked they too could be causing the problem your experiencing.
Once you get some of the console apart if any plastic parts are broken they should be pretty easy to spot.
Console replacement parts are not cheap and could be discontinued by now.
Good Luck.
========= Harryface =========
1991 Pontiac Bonneville LE, 3800 V6 _~_~_~_~274,049 miles_~_~_ ~_~_