[zelrik911]

You will probably need at least one 'slider' as well as new needle bearings under the gears. So it may get expensive fast!

I would also look out for a good used 5th gear set too. 5th gear wears when there is too little oil in the box. Its easy to underfill a 915 box - I always fill them in 2 goes, with a rest between because you can have oil coming out the fill hole when its only 2/3 full.