Looks cool for sure, but it looks like it's going the wrong way


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Maybe you should flip it around and its rotation would be right


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Tow it instead of pushing


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Will the gearbox from your original deck interchange? Are the rotations opposite?

 

Probably won't work. You are thinking of being able to 'flip' the ring gear like in an old VW transaxle. Unfortunately the JD box only has one output. There is no 'other side' to be able to swap the output gear to.

 

@rayjay

Yes, you basically get my point.

When looking at the gear box its obvious that it is a common cast for both the through axis gearboxes and this angular one. On the backside of the spline axel there is a frost plug kinda lid, that may allready feature a secondary bearing behind it, and it may or may not at least feature an already machined seat for a bearing. Regardless it is probably possible to machine one bearing seat there.

If that's the case, and the gear has straight cuts, it might be possible to move the primary gear to the opposite of the axle, or at least fabricate a brand new axle with the gear on the opposite side.

Only definite hinder, as I can see it, would be if the outgoing gear has an axle or nut or whatever that sits physically in the way of an through-going primary axle.

It is a long shot of course, but if someone have had theese gearboxes apart for changing bearings or whatever, they might recall the design?

Made an explanatory picture if it helps to get my idea.

Any new insights after this?

 

Look at the exploded view on the JD parts site.

 

just a guess but maybe you could x-cross the belt and rig up a metal deflector so it doesnt actually touch itself at the x-point

 

We must have had the same thought at the same time


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Which part is belt driven, maybe you can twist a belt like on a 31 tiller to get the rotation reversed, it would be hard to size but it might be worth a try


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I've thought aboute twisting the belt. Would be between crank pulley and gearbox in that case. However it's a pair-belt drive, and to be able to twist it, I would need to run it single and considering the increased width of cut, I really think that pair-belt is appropriate.

As for the exploded view, I cannot find any sub-categories beneath the assembly that shows the gearbox as it is.

I guess my only chance is to open the gearbox up to find out.

But as always, further tips is highly apprechiated.:thanku:

 

I've thought aboute twisting the belt. Would be between crank pulley and gearbox in that case. However it's a pair-belt drive, and to be able to twist it, I would need to run it single and considering the increased width of cut, I really think that pair-belt is appropriate.



As for the exploded view, I cannot find any sub-categories beneath the assembly that shows the gearbox as it is.



I guess my only chance is to open the gearbox up to find out.



But as always, further tips is highly apprechiated.:thanku:

Just get a B belt, they are about 2 times thicker then a regular belt, if you knew the size and it worked you could get one at Graingers


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I would just see if you could sell it to someone in Australia... Rotation is probably correct for Southern Hemisphere.


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If you are using straight cut blades or blades without a back lift, rotation of the blades vertical to shaft by 180 degree's may solve the problem.

 

Haha, Why didn't I think of the Australia thing. Just the perfect sollution would be to move there.

As for rotating the blades, they have a lift. So I would have the sharp edge leading but approx 1" above the lowest part of the blade.

But I will today try to source a longer belt, and give that sollusion a proper try. So thanks for the feedback on that, I will get back with reports on the results.

 

From looking at the parts diagram it may be possible to machine the output shaft and put the driven gear on the opposite side. There are two main issues that will make it very difficult to do right.

Firstly the tapered roller bearings require a certain amount of preload when assembled. The existing amount of preload will be lost when the shaft is machined to take the driven gear in it's new location.

Secondly the driven gear has to be positioned accurately in relation to the drive gear for proper engagement. I don't see any way to measure this location so the only other way would be a bunch of tedious disassembly and reassembly to use trial and error shimming. This shimming could also correct the lost brg preload. Too loose or too tight on either the gear engagement or brg preload would result in rapid wear of all moving parts in the gearbox.

 

Here is something that might help

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@rayjay

Are you sure there are tapered roller bearing and not regular ball bearings? Can you see this on the parts diagram? If so, please direct me to exactly where you found this information. As for shimming, one could measure both axial play and also torque with a proper gauge, before disassembly, in order to get it somewhat right.

I've done restorations of translaxle gearboxes before with tapered roller bearings and that was the described method.



As for the belt length, I went out to remove the old one, but realised that it was in fact possible to cross the current one due to excessive travel on the tensioner. However when I fired it up, it only gave a small twitch at the pulleys in the deck, before it popped of.

Likely a result of the special tensioner on the F725, and might be remedied with another tensioner type, but its a bit of work to start to modify or fabricate a new tensioner, without knowing for a fact that it will work afterwards. As to exactly what happenes when it popps, I need to rig a slow-motion camera or at least have someone assisting me to try to figure it out.

Story continues, I would really hate to give up.

 

Then just buy blades without the lift and put them on like another poster said


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@David

I've considered it.

Only downside with that is that the 7-Iron flex has a quite intricate pulley system which is designed to have the the tensioners on the loose/secondary side of each belt drive. By running it the other way, I will pre-tense these when I apply load on the drives, and have a flawed tension funcion. However I have allready driven it like this for 30min before I realized I had a problem at all, and haven't really seen any real effects of this. Decresed belt life is likely the only practical effect however.

It might be the solution with least amound of compromise after all, but I'm evaluating the others a bit more.

A crossed belt would be the best one of I got it to work.

 

Put the belt in a figure 8, going to pto shaft.

Is the gear box on the old mower deck a reversed turn? I would probably take it off the old deck and fit it to the new deck.