utility tractor transmission question

[robbie]

I want to build a utility tractor to pull a wagon on my farm. It will be used to haul dead pigs for butchering, watermelons, hay, firewood, rocks, etc. I'm aiming for a maximum gross weight of 500 to 600 pounds.

I could use one of the large expensive engines from Harbor Freight, but I won't be cutting grass and I won't be going fast with a load. I may build it with an alternate ratio selector for going moderately fast without a load, but that's still optional.

My question is about the transmission. I saw what happened to Chris's transmission when he put high-grip tires and extra horsepower on his tractor, so I'm cautious about using one. Should I avoid lawnmower transmissions entirely and simply use a Predator 212cc engine and a torque converter? It could drive a belt transmission to allow me to select high or low speed, and another selector to go in reverse.

 

[exenos]

If you used a peerless 820 or 900 series transaxle it will hold up to more power than you can reasonably throw at it. Also look into some of the older 3 speed hi/low transaxles, specifically one with a horizontal input. Most were in garden tractors and were made to handle plenty of power and very heavy loads. The one I have came attached to a 18hp engine and it's approaching the size of a transfer case. If you can find something like that I don't think you'll have any problems at all.

 

[loud1]

You can check out surplscenter.com they have a lot of transmissions to choose from or at least get info about.

You can always look into making a Mini-Beep.

 

[Doc Sprocket]

If you used a peerless 820 or 900 series transaxle it will hold up to more power than you can reasonably throw at it.

It was a 900 series that I shattered. The 820's are supposed to be pretty strong. That said-

I am already planning my next utility tractor thingy, MULEII. Plans call for a Peerless 700 transmission (NOT transaxle) and a live axle, likely 1 1/4" solid shaft, no diff. What you do not have, you cannot break.

Also- I did not add any appreciable power. I am running a 15hp OHV Briggs single in MULE, it shipped with a 12hp engine. These transaxle come shipped behind larger engines still. The problem was not in the torque, or the traction. It was in a bad bounce that caused a hard shock load on the right side of the housing. An axle truss would likely have prevented it. I am planning on building a truss for MULE.

 

[robbie]

So, the failure was in your frame, not the axle itself. That makes sense.

When I was a kid we had an old Montgomery Wards garden tractor with a 14 hp Briggs and a long drive shaft mounted to the engine. It went back to the transaxle, which had a car-style gear shift lever. There are a couple of old tractors in the scrap yard with this kind of arrangement, which would be a lot easier than building an entirely new tractor. The transmission would be so strong I wouldn't ever have to worry about breaking it.

 

[Doc Sprocket]

Yes, and no. The frame would have tweaked a bit, but I also found what I am going to call an inherent weakness in the transaxle design.

And again- I believe the transaxle is to be generally avoided, in favour of a separate transmission and axle.

 

[robbie]

What about an old 1970 style transaxle made of iron instead of aluminum?

 

[Doc Sprocket]

Iron=good, for sure!

 

[robbie]

I think it would be pretty hard to crack one of those up. Next time I get a chance I'll go to the scrap yard and see what's there.

Have you ever considered building a small utility tractor with a rear axle from an old Corolla or Datsun? You could use a torque converter to drive a sprocket attached to the differential input.

 

[Doc Sprocket]

Yes- and golf cart axles can be pretty stout, too. It's really a matter of what you can lay hands on, and what's going to best suit your purpose.

For MULEII- I am deliberately avoiding a differential for ultimate traction. With a solid live axle of say 1 1/4", and well-supported, I'm sure it will go the distance.

 

[robbie]

Are you going to put one giant Fred Flintstone wheel on the back?

 

[Doc Sprocket]

Nooo. Two. Two big snotty ATV tires, size and type currently unknown. I have a few possible options, and I'm even thinking about maybe duallies or a tandem, but that's for another thread.

Please- do keep me posted on this!

 

[exenos]

It was a 900 series that I shattered.

SNIP

My bad then. I was under the impression that the 900 series was just the 820 with a 3/4 shaft instead of a 1".

 

[robbie]

Nooo. Two. Two big snotty ATV tires, size and type currently unknown. I have a few possible options, and I'm even thinking about maybe duallies or a tandem, but that's for another thread.

Please- do keep me posted on this!

I will. I need to go anyway to get some parts for a riding mower. I've seen the old tractors over there before, but this time I'll take a closer look.