I too had same problem on a pride XL8 scooter, the local dealer wanted megabucks for a replacement transaxle,(on 5yr old machine), but instead i purchased a full machine off ebay for £90, as spares,.
Reason for failure in first place was lack of lubrication, so i made sure it was well lubed on assembly, result,,super,machine runs well, and i got a shed full of spares to go at,
james, July 2008