When my car changes gears while accelerating, it clunks and lurches....?

It started just today. In fact, if I have it in ';neutral'; and I put it in ';drive'; with the hood open, you can physically see the engine move a bit... What the hec is going on?



I'll take it to a mechanic, but I'm just wondering what this could be and how much it'll run me? It's a 2004 Saturn L300.



Also, this is before my schedule says I should change the transmission fluid, so I don't think it's that.When my car changes gears while accelerating, it clunks and lurches....?
Throttle Position Sensor Bad causing RPMs to be too high.



Transmission Fluid %26amp; Filter need to be changed and Transmission Flushed. ';But 2004'; Doesn't sound right, Hard driving or high Mileage? could account for it!



Torque Converter Went bad.



Cost all depends what they find wrong!When my car changes gears while accelerating, it clunks and lurches....?
sounds like a defective transmission mount.
You need your engine mounts replaced. You probably have hydraulic engine mounts and they're worn out. That why you see the engine moving, and hear the clunking.
Defintiely sounds like a rubber mount has broken on the engine or gearbox. It's not a disaster by an means and it's worth having a look to check if it is not just the bolt holding the mount that has come undone. There are usually 3 mounts on the engine and the most common one to give up is the one at the front at the bottom of the engine. Engine mounts only cost $20 and might take an hour or two to fit.