Hey everyone... Im have some troubles with my car. Its been shaking for a bit now and im still driving it around and my speedometer never worked correctly but now its just doesnt work at all. and my car shakes even more i think its coming from the tranny. Also my transmission fluid is BLACK its darker than my oil. But i cant tell if it smells burnt or not?.. When my speedometer used to work a little it would work on and off. when it actually worked everything ran great it shifted on time and everything but when it wouldnt work it would just stay in one gear until the Rmps would hit about 5000 and then it would shift. NOW the speedomter wont work at all and when i accelerate it shifts up like at 5000 rmp and then goes to 3rd gear the next second and it runs at 2000 rpms but shaking alot. and when i stomp on the gas i hear a loud knocking noise. So whats up with my car? i recently got the head gaskets repaired and my cat converter. Thanks.. Oh yea also when im idling i get 0 oil pressure and the check gauge light comes on but when i rev it up it goes up ? but i never seen the oil pressure gauge half way. ?

 

You could be killing your engine every time you start it up. First and foremost you NEED to find out why you have zero oil pressure and for the love of all things holy you must stop the "rev it up..." routine. If indeed your pressure is low, every time you start the engine it could cost you more for a rebuild.
You need to see what codes have been triggered. If anything for your peace of mind, however I'm not sure it even matters at this point. Zero oil pressure and knocking are never a good thing.