Two-Speed PTO Modification for M4900 and M5700

[rbargeron]

I posted a couple years ago about adding a 2-speed pto to my L5450, so it has selectable 540 and 750 rpm speeds. At the time I didn't know if this modification might be possible on other models too - but it may be.

I was looking at Kubota's Australia website today, where they describe the M4900 and M5700 as follows:

"Both models are 4 wheel drive and incorporate an easy to use 12 forward/12 reverse speed, full synchro shuttle shift transmission. Standard speeds range from 0.4 to 29kph, and the hydraulic PTO ensures smooth implement engagement. 540 or 750 PTO speed can be selected via a shift lever, and the PTO shaft can be rotated 60 degrees with the engine off for easy implement hook-up. "

If, like the L5450, the parts catalogs for these tractors list the parts for all countries, the appropriate bits and pieces could be ordered and added to US spec machines. This is a useful modification. For all those jobs that don't need full pto power, the engine rpm can be down around 1700 while still spinning the implement shaft at 540. It saves fuel, heat and wear.

Hope Kubota's liability lawyers don't send me a nasty-gram. /forums/images/graemlins/cool.gif

 

[ns_in_tex]

I very much would like to find some way of doing this to my L4610 HSTC for finish mowing purposes. The only thing I have found is a gear box, but it is a 2 to 1 ratio which I think would be a little slow engine speed for my 7' mower.

 

[rbargeron]

At the Kubota-Australia website the M4900 and M5700 are the only models I found with 2-speed pto's - the Lxx30's show just single-speed pto, as does the L4300. My guess is that the Grand L10's were also single speed.

I think high-speed implements are also sold in Japan - so it seems possible 2-speed pto's were offered on Lxx10's there. Maybe some enterprising person here at TBN knows a way to access the parts lists. In my case my tractor was part of a model line that not only had 2-speed pto in Australia/New Zealand, but once had 2-speed pto's on US models too so the needed parts were stocked in the US.

Gearboxes for pto speed increase are tricky - they need to be about 1:1.5 - I agree with you that 1:2 may be too much. They also need input and output to turn in the same direction - not an everyday product. A gear company in the midwest (name escapes me) used to produce such a box for tractors - may still. I do remember it was not cheap. One went on ebay recently for about $200 - a very good deal if it was in decent condition.

 

[slowzuki]

You'll notice the note on the Aussy website that says the specs shown for the L30's are the Canadian specs at the moment.
Ken

 

[rbargeron]

Sharp eye ! So there's hope. It seems too bad that Kubota saw fit to take away the utility of a second pto speed from the North American market. I can't help but think it was to "protect us from ourselves" like so many product design decisions these days. An engineering professor once told us "when you design something to be foolproof, you simply give rise to a new whole class of fools". It's a little harsh but it has a ring of truth to it.

 

[L3710GV]

Probably to do with liability

rbargeron- have you thought about actually changing those gears, it would be a very big job splitting case to get at those gears /forums/images/graemlins/frown.gif Not that its bad idea-just alot of work

 

[JerryG]

Kubota may not be importing the 2 speed for the same reason that Massey isn't. In the work shop manuals, MF says that they have only the 540 because the other speeds are not authorized, up to the same standard or something to that effect per ASAE standards. I should have looked it up again before I made this post.

 

[rbargeron]

On my tractor the pto gearcase was at the back so it was easy to take apart. There are pictures of the job here (starting halfway down the thread).

For the M4700,4900,5400,5700 models the Aussie description also mentions a 60-degree free-turn on the pto shaft - sounds like the 2-speed pto feature is contained in a separate housing on the back end, which could possibly be bought separately thru a friendly AU/NZ dealer, if not a US one.

Changing a tractor's existing single speed 540 pto gears to a different ratio would be a major undertaking beyond just the disassembly. Would need to know center distance, pitch, pressure angle, finish, hardness map, internal spline specs, hub thickness, offset, shifter collar dimensions, etc. etc. To make them from scratch, the first pair would cost more than a new tractor. Maybe a group buy of 1,000 sets? /forums/images/graemlins/tongue.gif

I think Jerry is right - ASAE standards are moving the world toward the single 540 speed for the 1-3/8" 6-spline pto. Just not everybody making implements around the world is in compliance yet.