changing gear ratio in 600/800 series

[William Fissell]

Hi, All,

I use a MF 35 to run a 5' tiller on my and and even in 1 low its a little quick. My 640? No way.

I know there are a variety of step ups and step downs that were aftermarket or dealer options.

I was wondering about substituting a different pair of gears for 1st gear to give the tractor a lower ground speed in first. I dont imagine they'd be off the shelf- you'd have to make them, but there are talented machinists among us. My only thought was that the transmission housing might not physically accommodate a larger first gear; its been a minute since I looked inside one.

thoughts?

thank you

640 going strong
861 awaiting in frame
TO-30 going strong
TO-35 going strong
TO-35 getting reassembled after engine rebuild

 

[cdmn]

Check the 1971 or newer Dexta. They had a slower 1st gear that works for tillers.

 

[Sean in PA]

(quoted from post at 21:30:11 10/16/22) Check the 1971 or newer Dexta. They had a slower 1st gear that works for tillers.

They stopped making the Dexta in 1964. Did you mean 1961 or newer?

 

[Husker 50 8n]

Get the 861 going. 1st gear is slower in the 5 speed transmission. Gears 2-5 are about the same as gears 1-4 in your 640. I've run my 72" tiller with my 861 and my 4000 with SOS. The SOS works very well with a tiller, gears 1-3 are very slow.

 

[cdmn]

Sorry

 

[Majorman]

The Ford 2000 was badged Dexta and the 3000 Super Dexta until 1968 so it is an easy
slip.

 

[Sean in PA]

(quoted from post at 03:30:20 10/17/22) The Ford 2000 was badged Dexta and the 3000 Super Dexta until 1968 so it is an easy
slip.

But not up to 1971.

 

[Dean]

Auxiliary transmissions, aside from the very rare and equally fragile Howard, will not make your 6/84* tractor suitable for tiller use because they also slow PTO speed. The only Ford tractors of similar
vintage suitable for tiller use are the SOS models.

 

[William Fissell]

Interesting. The ground speed for 1 low in MF35 says 1.2 MPH vs 2.2 for the Ford 5-speed. I wonder if your tiller turns
faster than my 60 inch gray market kubota?

 

[Majorman]

Agreed.

 

[William Fissell]

Hi, Dean!

Yes, i know, thats why I was wondering about chnaging out the gears for first gear wiht a different ratio to lower the ground spped!

thnaks,

Bill

 

[Sean in PA]

(quoted from post at 10:57:42 10/17/22) Hi, Dean!

Yes, i know, thats why I was wondering about chnaging out the gears for first gear wiht a different ratio to lower the ground spped!

thnaks,

Bill

Would have to be custom made for sure, and as you pointed out, might not be able to fit a large enough gear into that space.

Another option is the Howard auxiliary transmission. That one reduces the speed at the output side of the main transmission rather than the input side, so the PTO can run at full speed while the rear wheels are running at a reduced speed.

 

[Destroked 450]

(quoted from post at 02:30:20 10/17/22) The Ford 2000 was badged Dexta and the 3000 Super Dexta until 1968 so it is an easy
slip.

Maybe on the European models but all, we have a 66 3000 and 66 5000, neither one has the Dexta or Major script, just the numbers and both are original paint

This post was edited by Destroked 450 on 10/17/2022 at 09:33 am.

 

[Dean]

With enough money and/or time, many otherwise impractical things can be done, but there is no cost effective way of doing this.

 

[William Fissell]

None of this is

 

[cdmn]

I have wondered what would happen if you replaced one or both axle housings with
4000 planetary axles. With only one, it may go forward or reverse. Have to think
about that. With both, it will go in reverse, so you need to flip the ring gear.
I think that would slow it by about 3-4 times. Top gear would be about 5 mph. You
would need to adapt to the rear housing and differential splines.
With just one housing converted, I would guess the effect would be one-half, but
the spider gears would have to really whirl.

 

[Sean in PA]

(quoted from post at 15:08:53 10/17/22)
I have wondered what would happen if you replaced one or both axle housings with
4000 planetary axles. With only one, it may go forward or reverse. Have to think
about that. With both, it will go in reverse, so you need to flip the ring gear.
I think that would slow it by about 3-4 times. Top gear would be about 5 mph. You
would need to adapt to the rear housing and differential splines.
With just one housing converted, I would guess the effect would be one-half, but
the spider gears would have to really whirl.

The only 4000 that had planetary gears in the rear axle was the 3 cylinder 4000 series. I doubt that axle trumpets from a 3 cylinder 4000 would bolt up to a center housing from a hundred series tractor.

 

[Lynn Patrick]

Sounds like a LOT of work for the one result. Would it make more sense to simply add a gearbox between the pto & the tiller drive?? Just wondering!

This post was edited by Lynn Patrick on 10/17/2022 at 04:40 pm.

 

[JMOR]

(quoted from post at 19:39:45 10/17/22) Sounds like a LOT of work for the one result. Would it make more sense to simply add a gearbox between the pto & the tiller drive?? Just wondering!

This post was edited by Lynn Patrick on 10/17/2022 at 04:40 pm.

o get a capable machine shop to make such gears, if even possible, would likely cost more than the tractor is worth. Forget tiller or buy appropriate tractor.