tailshaft bushing

The tool their refering to is a bushing driver. Bushing driver sets are sold through tool vendors (Snap-on, Mac, Lisle, etc) but you may have trouble finding a set with the right size you need. I haven't done a 904 but have done several 727's and with them I just found a heavy wall piece of pipe that was about .010-.030 smaller than the OD of the bushing and used it to drive out the old bushing. Then to drive in the new one I laid a thick washer I had on it and drove it in using the pipe again. Just make sure it's centered perfectly or you can damage it real easy.

If you can find a bushing driver set that will work and can afford it it'll sure make things alot easier and ensure you don't damage the new bushing. The way I do it is the poor mans way.