B7100D HST transmission disassembly advice

[taranakiguy]

Hello fellow Orange Tractor Owners... I've stalked these threads during my brief stint as a Kubota owner to answer most of my questions so far... but I have come to the point where I could really use some advice/direction.
Firstly a little background. I recently purchased a Secondhand Kubota B7100D HST Serial number B7100HD54847 Proud as punch I was as I set about taming the tall grass on our section using the Tractor and the PTO driven Mulching mower that came with it. Everything was working superbly for a couple of hours and then the PTO started making a terrible noise! Long story short... I have disassembled the tractor to the point that I have found (and can clearly see) the problem, See Pics attached. But I am now stuck on how to actually disassemble the transmission and extract the various shafts and cogs so that they can (hopefully) be replaced. The work shop manual says "Disassembly is evident after reference to Figs 74 and 79" but I have to admit to being a bit stumped on how to proceed with the disassembly.
Can anyone offer any advice on how to proceed or point me in the direction of a resource that might help explain what to do?
Any and all help greatly appreciated

 

[85Hokie]

Do you have a good set of offset snap ring pliers?

Finding that gear might be a chore too - specially in your location - and if found, I cannot even guess as to the cost!

Do you have a machinist around that could make that if need be?

If you can log in here :

https://www.messicks.com/ku/84587.....

Part breakdown.

 

[taranakiguy]

Thanks 85Hokie,

Yes pair of Offset Snap Ring Pliers ready to use, just not sure in what order to use them?

Thanks for the link to Messicks, in my research I've visited their site and think I recall seeing that they will ship to my part of the world (assuming they have what I need) but yeah, also not looking forward to tallying up the costs!

If I cant get the parts, I'll do as you suggest and investigate a machine shop to mill some replacements, (assuming I can get the offending parts out)

 

[Russell King]

Take plenty of pictures first and possibly mark the gears and shafts and case so you know where they were before disassembly.

I am only guessing at disassembly steps but you can remove the circlips, remove any covers at the ends of the shafts and possibly slide the shaft out through the gears and case?

If there are no through holes in the case see if the shaft can slide far enough one way to have the shaft end come out of the case. Again the gears may need removal first unless there are clips near the case wall.

Be sure to wear safety glasses when removing the clips and try to rig up something (rags, something holding clips) to keep the clips from flying too far.

Hopefully some more experienced people will be along to tell you more details.


Sent from my iPad using Tapatalk

 

[SidecarFlip]

Gears aren't milled, you hob them on a gear hobbing machine. You can cut them on an engine lathe but a shop with a gear hobber is what you want if you cannot fine the gearsets and they will need to be heat treated as well.

 

[North Idaho Wolfman]

Give me the serial # so I can pull up the right diagrams and I should be able to help you out.

I'm getting ready to split one I have here, to replace the transmission housing, so, maybe I'll just dive into this one and I can give you some exact details on how it all comes apart.

 

[taranakiguy]

Thanks SidecarFlip... appreciate the advice on what to ask for if I get to that stage... Will be googling Gear Hobbing in Hamilton NZ to see what pops up. And yes I understand that if I need to get them made, I will also need to ensure that they are heat treated. Thanks again for your advice.

 

[taranakiguy]

Thanks for your advice Russell. Will ensure I take plenty of pictures and I also have a label making machine at the ready... I intend to mark the components with the item numbers from the WSM. hopefully that should help ensure I can keep track of what is what should I end up with things a bit mixed up. Also great advice about the safety glasses when removing clips.. I had previous experience of them shooting across garage when things do go quite right!

 

[taranakiguy]

Thanks a million for the offer of assistance North Idaho Wolfman the serial number of the Tractor is 54847 assuming I have read that right from the side of the machine... There is a digit after the 7 which looks more like a O (Oh) with some marks in it rather than a 0 (Zero) Ill try and upload a photo of the serial if that helps

 

[North Idaho Wolfman]

Thanks a million for the offer of assistance North Idaho Wolfman the serial number of the Tractor is 54847 assuming I have read that right from the side of the machine... There is a digit after the 7 which looks more like a O (Oh) with some marks in it rather than a 0 (Zero) Ill try and upload a photo of the serial if that helps

That symbol is the Kubota Logo.

Give me a bit to dig into this.

 

[Lil Foot]

At the risk of starting a debate/flame war:

Gears aren't milled, you hob them on a gear hobbing machine.

Wow. Never knew I was doing the impossible all these years. I have probably milled or broached near a hundred gears over the last 40 years. I think I even still have some gear tooth cutters in the stash.

While hobbing is the preferred method, especially for production, it's certainly possible to mill gears, especially for lower speed, lesser precision applications.

I probably wouldn't try to mill a gear set for a 600mph Bonneville racer transmission, but I might mill a replacement gear for a tractor transmission.
Oh wait, I already have, and it is still in service after 30+ years.

And before anybody gets any ideas, for most of my career, I had access to a huge, very capable, very diverse aerospace machine shop with all the trimmings. (except a gear hob ) I currently have a small garage shop, and (because of the caregiver thing) I don't have time to do my own machining, let for alone anyone else.
You couldn't afford me anyway.

Edit: I looked for those cutters and can't find them; either the memory is bad (quite likely) or I put them somewhere where I wouldn't lose them, and lost them. (more likely)

 

[taranakiguy]

That symbol is the Kubota Logo

Ha Don't I feel like such a Noob

 

[taranakiguy]

And before anybody gets any ideas... I don't have time to do my own machining, let for alone anyone else.
You couldn't afford me anyway.

Thought you were the answer to my prayers for a second there Bill.
I'm certainly not qualified to debate the correct or best method to machine new gears... my workshop consists primarily of handheld power tools lol

 

[Lil Foot]

Yeah, sorry. IF my life was a little different, maybe, but it's just not possible these days. Not how I planned spending the best years of my retirement.

 

[Lil Foot]

By the way, I hope this works out for you, with lots of pics & documentation of the teardown & rebuild. Someday I will have to do mine- everything works, but second gear is noisy at higher speeds. (bad bearing? worn teeth?) It's OK for now, but the handwriting is on the wall.

 

[taranakiguy]

Give me the serial # so I can pull up the right diagrams and I should be able to help you out.

I'm getting ready to split one I have here, to replace the transmission housing, so, maybe I'll just dive into this one and I can give you some exact details on how it all comes apart.

HI North Idaho Wolfman, I just wanted to let you know (hopefully before you have invested any time in trying to document this for me) That I have had some success today! I felt sure that the transmission casing should separate from the axle housing... but try as I might the two wouldn't come apart... I discovered today that they do of course come apart... provided you have remove ALL of the nuts holding the two together... I had missed one that was covered in dirt and grime and partially obscured under the 4WD lever! I feel like a bit of an idiot! As once the two housings are separated, is is indeed evident how the disassembly proceeds.
I'll try and post some pics and more of an update a bit later, but just wanted to let you know so that you don't spend time on this on my account
Cheers

 

[North Idaho Wolfman]

HI North Idaho Wolfman, I just wanted to let you know (hopefully before you have invested any time in trying to document this for me) That I have had some success today! I felt sure that the transmission casing should separate from the axle housing... but try as I might the two wouldn't come apart... I discovered today that they do of course come apart... provided you have remove ALL of the nuts holding the two together... I had missed one that was covered in dirt and grime and partially obscured under the 4WD lever! I feel like a bit of an idiot! As once the two housings are separated, is is indeed evident how the disassembly proceeds.
I'll try and post some pics and more of an update a bit later, but just wanted to let you know so that you don't spend time on this on my account
Cheers

Thanks and really glad you got it apart!

I'm stuck in a rain delay right now, normal for this time of year.

 

[torch]

Edit: I looked for those cutters and can't find them; either the memory is bad (quite likely) or I put them somewhere where I wouldn't lose them, and lost them. (more likely)

Bill, no problem. Get some O1 and make a replacement. It'll do for a one- or two-off project.

Step 1, make an insert of the appropriate diameter:

Step 2, mount hardened insert to a piece of steel and install in tool holder:

Step 3, use hardened O1 to cut another piece of O1 to the correct form:

Step 4, cut it into teeth before hardening and honing:

Voila! Now you have a cutter, ready to mill your own spur gears without hobbing:

(Inspired by the work of Ivan Law in his handbook "Gears and Gear Cutting")

 

[Lil Foot]

torch- Yup, done lots of that sort of thing over the years, but the problem is that now I don't have the time to cut gears for people even I had the cutters, let alone enough time to make the cutters too!
Thanks for posting, I seldom got to photograph anything like that, & I'm sure folks will find the process interesting.

 

[taranakiguy]

Just as an update to this... I've got the girl purring like a kitten again.
I managed to find the two replacement gears I needed (2nd Hand) from Wengers at a mere $350 $USD (cough cough) Then I had to ship them to NZ.
Also ordered a complete gasket kit from Coleman Equipment for every join I had taken apart for $60 $USD. This also included a new main O-ring for the 3 point linkage Hydraulic ram... as it would drop quite quickly with the mower mounted on the 3 point linkage, and I suspected that the O-ring was the root cause. I had numerous hours of *fun* reassembling the transmission... especially after sitting apart for the month it took to get the gear together. Eradicating the metal flakes from the old gears was not as simple as it i though it would be... including using a powerful electromagnet to extract the metal filings from the hydro-static drive filters... (yes in retrospect I should have ordered new ones of those too.) Reassembling the two halves of the tractor by myself was also an exciting challenge, but nothing a large ratchet strop wasn't able to fix. The PTO now purrs like a kitten and engages both High and Low speed smoothly (unlike when I first brought the tractor 2nd hand) And as a bonus, my $2 O-ring has made a huge difference to the mower staying at the required height without dragging the 3 point linkage down.
Next exciting challenge will be to see if I can get a crowd action loader from a Kubota B1-16 to fit my B7100D...??? How hard can it be right?
Got a 2 hour drive tomorrow to go and pick one up so fingers crossed I can make it work!