Gearbox Whirling

  1. #1
    As above, my gearbox is making a whirling noise when slowing down through the gears, never used to do it before. Someone has told me that it is possibly the Input Shaft bearings as they are Plastic casing and most likely have broken? these can be uprated to metal ones i have also been told.

    How ever i have a gearbox i can put on it, is this is a simple job to do ? is there any guides?
    i am going to have a go at it myself with a mate as we're both pretty mechanical minded and confident to do it.