I have a 95 Lumina 3.1 and it would cut out of gear when I would stop, it turned out to be the sprag gear in the transmission. $$$$
Will it run in park? What about neutral? Is it fuel injected? Have you changed the fuel filter?
If your stick shift will not move or if it will move but the car is not shifting gears, it is broken. If it feels very loose and is not catching on any gear then it is broken.
There could be two reasons for this. The first is the transmission is completely out and the second is the linkage in the transmission is broken.
Try changing the transmission fluid and filter
your transmission is burned out, the 1st and reverse clutches are worn out
front caliber seized
When your car doesnt move anywhere when its in gear just like any other transmission
The clutch is master and or slave cylinder are bad
If the brakes are out then you have no business putting it in any gear because it is unsafe to drive a car with no brakes.
A little more info can be helpful as to what make, type, year for us to help on the answer. Not trying to be rude, just throwing that out there. Its a 1997 Honda accord. We replaced the left front axle and the tire just spins and the car with no go into any gear other than park.
Most likely a broken gear cluster