Where to find gearbox/jackshaft for JD 660 tiller

johnpdo · Nov 10, 2018

OK, I bought a well-used 660 tiller. After tilling about an acre, it decided to trash the gearbox. Housing is scrap, and gears inside are also trashed. I would need a new gearbox and jackshaft combo.

Is is worth fixing? Where can I find that part. The JD dealer says 2-3000 for parts/labor. Heck, I can buy a new tiller for that.

Give me some feedback, please.

pmsmechanic · Nov 10, 2018

The gearbox housing is JD part # PT8798. Googling that gets a price of about $1125. The small gear is part #8800 $400. The large gear is part # 8801 $500. So about $2000 just in the three main parts.

I believe the rototillers were made by Howard but I didn't have a lot of luck looking for Howard parts diagrams. Maybe someone else with more time....

johnpdo · Nov 10, 2018

Thanks.
Once I get my box of parts back, I'll see what is salvageable
.

flyerdan · Nov 10, 2018

For that kind of money, I'd look at getting a rear axle from a small car and weld the diff. Might take some fussing to get the gear sprocketing right, but should be a fairly cheap solution.

pmsmechanic · Nov 10, 2018

Small drive gear off of pto shaft is 13 teeth. Large driven gear is 23 teeth. 1.769 reduction ratio. You won't find that in a small car diff.

I'd look for a 30 - 40 horse power gear box from Surplus Parts and see if you can't find one close to that. It would still take a bit of fabrication.

They are good rototillers. I'm just finished wearing out my 4th set of tines. They'll need to be replaced in spring. Other repairs have been the clutch and the seal on the tine rotor. The pto shaft split but I welded that up and I've had to do a few welds on the top mast. Still on the original chain and all the bearings.