vauxhall frontera 2.2 16valve 1995 gearbox/transmition?

there is 2 questions i have a seconhand gearbox/transmition that the gearbox is round the oppersite to the one on the car ie the starter motor and the hydrolic clutch arm are on diffrent sides to each other can i still fit them just change them over to oppersite sides .
question 2 there is a grating noies ie like teath rubbing to gether as i start moving from about 3 mph not from diff at back sounds like from gearbox/transmition does not make noes when engine is runing idle and gears change smooth but it only started doing this when i put it into 4 wheel drive and put it back changed the center bearing race on transmition center shaft and still making noies center shaft bearing had gone into bits thats why i thought it could be the problem please help marek