There are several things that can cause your transmission to slip, while first pulling out. The most common cause is a worn drive gear.
If it's an automatic transmission the linkage needs to be adjusted. On a manual transmission when it pops out of gear it means there may be a bad synchronize for that gear a mechanic will need to repair. Once in a while a manual transmission will start doing this if it is low on gear oil.
worn out trans most likely clutchs or oneway clutch <sprag>
Feeling the gears slip while driving or having a difficult time getting the speed past 30mph no matter how hard you press the gas pedal.
Your transmission might slip on your ML320 because the transmission fluid is low or because the transmission is damaged. The most common cause of transmission slip is wearing of the transmission.
2 possible obvious faults Ignition timing and\or transmission slip. Hard to say without knowing service history of the engine.
The neutral safety switch is located on the transmission shift lever. Its held onto the transmission case by 2 bolts in slotted holes. You will need to remove the kick down lever. The switch will slip off the shift lever with just a little pry if dirty. Replace the switch while the transmission is in neutral. There is a small hole in the side of the switch to stick a small pin or awl into to locate the neutral position of the switch. I would try to adjust the old switch before replacing it.
It is most likely a transmission slip, there is not much you can do to fix it your best bet is Lucas Stop Leak. While your transmission isn't leaking this will lessen the slip a bit. You will have to consider replacing the transmission after this one goes.
not usually,sometimes you get lucky and it will for a while. most of the time if a transmission has started to slip the damage is already done.
As it heats up, it slips more.
Check trans fluid level. If the fluid is up but smells burned or is not a nice bright red color, you may have serious transmission problems.
The engine also jumps when changing to Neutral and Drive. Should I have transmission fluid change? A/C was not on.