A friend just purchased a Bolens 17HP, 42 in cut mower. It appears to be a transmatic model 660-688? The left axle is working it's way out when I did a few turns in the driveway. Is there an easy way to fix this? I saw on the parts list that the differential assembly is not broken down any. Is that one unit that cannot be repaired? Also saw it is about $175 but is no longer available. He paid $200 and it came with a snow blade. It's in really good shape, saw the year 1998 under the seat. Can anyone help?