So I'm driving the X (E53 3.0 Diesel 2004) and I feel something is not right, I'm losing power, acceleration is limited at best, I turn down the music and I hear this terrible echoey metal scratching sound.

At higher revs the sound is louder, gears seem to change ok but it can not reach the power level to catch the next gear, manual gears seem operational too but again useless as there is no power, the noise is worrying aspect though as either something is broken or got jammed in somewhere.

Basically the car is not drivable in it's current state as it has no acceleration, and no Dummy lamps are on.

It will be going to the indy soon but I just want an idea of what it might be so I don't get robbed, looking like I might have an idea what the problem might be would certainly help

Please tell me it's something like water, oil or diesel.

Thanks fellas.