Some info would maybe help you. Permagreen has built 4 or 5 different iterations of its ride on spreader. There is the Centri, Ultra, Magnum, and Triumph. They dont all have the same transaxle. Depending on model it may be a peerless axle or something else. Either way, you need to look at the old transaxle and get the numbers off of it. You can probably get one that way from any dealer through the transaxle maker. However it will not come with the extra stuff that Permagreen does to them. I know the few I have gotten as replacements had extra coverings installed to protect them from the spray/spread materials.
Same goes for the pump. Numbers. Get them. Not Lesco numbers, numbers off the pump. Then contact http://www.contree.com/