Piece of cake if it's 5th on a 5-speed as it is at the end of the shaft - the difficult bit is taking the box off! Drained brown, yep dark BROWN, fluid from the Mrs's Suzuki gearbox after she was getting a serious whine then later almost scraping when decelerating. Turned out to be the first motion shaft bearing, a cage type with 7 ball bearings. Cage had disintegrated and all 7 ball bearings were grouped on one half of the races. As it was recessed in the bell housing it fortunately had not either broken the shaft, mashed the gears with the cage material nor collapsed. One NTK bearing later (£25) and some new Fuchs Sintopoid fluid (£15) and we have a quiet gearbox. Quoted £250 to £300 for the job by a gearbox firm near me. Winner!!