help: Gearbox and Engine

Hi everyone, I just bought an EG6 front cut from some spare parts place. Everything has been disassembled from the shell. Found that the gearbox oil is actually BLACK in colour and less than 1 litre. This really worries me. Also found that the gearbox is rattling when i spin the little metal rod sticking out from the gearbox. And also with the flywheel, I could see a lot of heat spots which leads me to believe that the car has been pushed very hard and probaly had a hard time. Just a few questions, I personally have not seen any black gearbox oil before and let alone that littlre. Is there any way how gearbox oil can turn black ?? And with that rattling noise in the gearbox, it sounds like something is loose. Could it be that the gears within the gearbox has been shredded ?? If anyone could give me a few suggestions, it would be good. Also, is it expensive to recondition a gearbox ??

prolly got mixed with oil, which could be your seal's on the motor could have blown as well, sounds like the gears got ate in there, it will cost alot of money to repair the tranny, id suggest you just find another b-series tranny and call it a day.

I was thinking of getting another b series gearbox but i am thinking i will risk going through the same problem again. There is a risk there that the gearbox could be Farked up as well. Any other suggestions ?? Also my b16a actually overheated before and there is this seal there right on top of the engine number. Is it bad that the engine has overheated before ?? I know it has been fixed. Took out the cover and I can see the cams are still okay.. slight burnt marks.. Any suggestions ?