I need to convert a small automotive differential (exact model is still discussable) to have a 12:1 (10:1 - 15:1) reduction in place of the usual ~3.5:1 ring and pinion gear.  I need to find a hardened worm and bronze worm gear at a reasonable price that could be modified to work.  The worm would go on a new shaft in a new location. (probably a new housing) The bronze worm gear would need to be large enough so that I could modify it (bore, face, drill holes) to mount to the differential carrier (~6"-9" diameter).  I'm sure that I could find what I want as a service part to an industrial speed reducer, but a brief look at industrial speed reducers tells me that I'd likely be into the thousands of dollars for this.  I'm hoping there is an agracultural device or similar that uses such gears and that would be a cheaper source  of parts??  I only need to transmit 30 hp or so, and the axle load won't be much, approximately 600 lb, with very little shock loading.  Alternatively, it would make me very happy if someone knows of a small axle that already has such a low reduction ratio - maybe used in a small tractor or similar?

Thanks for any assistance,

Mark

Disregard my question - I've found electric golf cart axles to be approximately what I need (without all of the fabrication!) so its just a matter of picking through them now.