needs adjustment most likely
There is a retaining mechanism in the transmission, it has worn out.
It must be an electric shift all the electric shift did that. and if the celluloids go bad it will give you forward and neutral so you can get off the lake.
if u are in a high gear no shift down because if u stay in the same high gear u will loose rpm as the car skids sideways causing a shorter drift.
What type of vehicle? possibly broken parking paw (not good) if it will park but shifter just wont stay you have a broken shifter safety switch (this is the switch that requires you to depress the brake to shift from park) if it is an older vehicle it is a broken shifter the button you press to shift is broken if it is your parking paw you will need a different transmission or take it to a transmission shop to have it worked on (paking paw is a small knob inside the transmission to keep the vehiclke from rolling and coould be broken if you park on hills without using the parking brake)
Jumping out of gear in a manual transmission is usually a sign of a worn detent in the internal shift linkage under the shift cover. This usually requires a rebuild of the transmission.
The shift lever cable may be damaged or out of adjustment.
If the 1999 Chevrolet Metro will not shift automatically there may be a problem with the transmission solenoid. The solenoid tells when the transmission when to shift, and when it is malfunctioning will cause a vehicle to stay stuck in a certain gear.
You should down shift ONE gear so it will keep your speed from increasing too much.. and occationally use the brakes to stick with the speed limit..
it is probably that your shift lever bushings have worn out, but check the rubber seals and carpeting, sometimes they put pressure against the shifter making it pop out of gear.
If the transmission doesn't see the right fluid pressures it will stay in second gear to allow you to get it off the road without tearing itself up.
The transmission may need repair or the shift lever may simply be disconnected.
my friend has a 2002 c230 and it has the same problem. it has 90,000 miles clean title.