90 Degree Bevel Gearbox on Kubota F3060 - 72" Rear Discharge Deck

[Capt.Ron]

My 1997 F3060 has what I think is somewhat rare RC72R-F30 Rear Discharge Deck and was just recently told by a dealer that Kubota is no longer selling replacement gearbox!

I was just looking to buy a spare gearbox but was unable to find anything offered online by the gearbox supplier either (Superior Gearbox Company, Stockton, MO) - in all fairness I never phoned them since I decided to look for alternatives first since the last Kubota list price for replacment was $631.39 (when it supposedly was still available)!


1. Superior 211ADF 189 6 Gearbox:

View attachment 704511





2. It was easy to find a Chinese made replacement gearbox on the eBay for $135
It is rated for 40 hp at 1500 rpm - the mower PTO runs at 2500+ rpm normally.

We will put some hours on it and update on longevity later - so far only about 3 hours of use.

View attachment 704509



3. The fit was perfect:




4. Shields etc. in place:




Like was said above this is just a spare gearbox, but I also want to modify the OEM gearbox input shaft and will machine 1/4" key-way & eliminate the shear bolt altogether.

The shear bolt only arraingment is causing a loose / sloppy fit in-between the driveshaft yoke and the gearbox input shaft.


I don't like buying Chinese stuff but unfortunately was not left with many other choices I could find and would have paid the OEM list price if it had been available!


Good to have alternatives & some competition!

I noticed that your pulley is painted gray. Did you paint it or get a new one?

 

[arto98607]

I noticed that your pulley is painted gray. Did you paint it or get a new one?

It's a new pulley since I wanted a spare, but it's 1/4" larger than original - no big deal.
I now run the engine at touch slower rpm just for the heck of it.


5.75" Single Groove Belt B Section 5L Pulley 1" Sheave Bushing BK60H Cast Iron | eBay

 

[Capt.Ron]

It's a new pulley since I wanted a spare, but it's 1/4" larger than original - no big deal.
I now run the engine at touch slower rpm just for the heck of it.


5.75" Single Groove Belt B Section 5L Pulley 1" Sheave Bushing BK60H Cast Iron | eBay

Wonder what that calculates to in blade speed at full RPM. Not sure I'm smart enough to figure out that calculation without causing smoke from my ears. LOL!
Might actually cut a little better.
Might grenade the blades and spindle bearings. YIKES

 

[arto98607]

Wonder what that calculates to in blade speed at full RPM. Not sure I'm smart enough to figure out that calculation without causing smoke from my ears. LOL!
Might actually cut a little better.
Might grenade the blades and spindle bearings. YIKES

No noticeable difference at all when using the mower.
I did rough calculations before ordering and decided no need to worry about 1/4" larger drive pulley diameter.

By the way, in my RC72R-F30 mower deck the spindle bearings are the same Timken Set 14 (L44643 / L44610), as the Superior gearbox bearings but the seals are different.

 

[Capt.Ron]

No noticeable difference at all when using the mower.
I did rough calculations before ordering and decided no need to worry about 1/4" larger drive pulley diameter.

By the way, in my RC72R-F30 mower deck the spindle bearings are the same Timken Set 14 (L44643 / L44610), as the Superior gearbox bearings but the seals are different.

OK, All my parts are in. I didn't think my old gear box was very loose but by comparison it's quite loose! Do you know off hand what thread size that is for the JD Vent? I assume it's an NPT thread?
Also, is there any reason why the gearbox can't or shouldn't be mounted so the round plate is on top?
Mounting that way would allow for drilling and tapping that plate while off of the gearbox. No need to completely disassemble the gearbox. The bolt pattern, unless I missed something is 4.25" in all directions.

 

[TractorGuy]

Was the Superior gearbox 1 to 1 also?

I put a 1/2" larger pulley on my finish mower to kick up the blade speed a little. Finish mower is a different animal with input at 540 RPM.

 

[arto98607]

OK, All my parts are in. I didn't think my old gear box was very loose but by comparison it's quite loose! Do you know off hand what thread size that is for the JD Vent? I assume it's an NPT thread?
Also, is there any reason why the gearbox can't or shouldn't be mounted so the round plate is on top?
Mounting that way would allow for drilling and tapping that plate while off of the gearbox. No need to completely disassemble the gearbox. The bolt pattern, unless I missed something is 4.25" in all directions.

It's 1/8" NPT-27, so 21/64" drill bit will work.


I mounted it so the round plate is on the side for three reasons:

1. I can check the oil level by using a screwdriver as a dipstick.
2. I can evacuate all of the used oil with a vacuum oil extractor.
3. The oil evacuator tube can be easily pushed all the way to the bottom of the gearbox housing where any fine wear debris (steel) should be.

If you dismantle the gearbox you will see why none the above will work if it's mounted the other way as you suggested.

 

[arto98607]

Was the Superior gearbox 1 to 1 also?

I put a 1/2" larger pulley on my finish mower to kick up the blade speed a little. Finish mower is a different animal with input at 540 RPM.

Yes the Superior has 1:1 ratio also.

 

[ROUSTABOUT]

All the kubota deck gear boxes are the same. Put a bunch in the dumpster. Didn't know anybody wanted one. Guy was packing all them mowers in a dumpster with a back hoe. Two big roll off dumpsters full. I worked at Kubota.

 

[arto98607]

All the kubota deck gear boxes are the same. Put a bunch in the dumpster. Didn't know anybody wanted one. Guy was packing all them mowers in a dumpster with a back hoe. Two big roll off dumpsters full. I worked at Kubota.

No they are not all the same - since you worked "at Kubota" you should know better!

See post #1 in this thread.

Mine is in F3060 and the deck gearbox was made by Superior Gearbox Co in Stockton, MO

The only trouble with it is Kubota no longer sells parts for it, otherwise nothing wrong with it.
The reason I got another (Chinese) gearbox is because I wanted to have a future spare on hand for the above reason.

 

[Capt.Ron]

Put a bunch in the dumpster. Didn't know anybody wanted one. Guy was packing all them mowers in a dumpster with a back hoe. Two big roll off dumpsters full. I worked at Kubota.

 

[Capt.Ron]

It's 1/8" NPT-27, so 21/64" drill bit will work.


I mounted it so the round plate is on the side for three reasons:

1. I can check the oil level by using a screwdriver as a dipstick.
2. I can evacuate all of the used oil with a vacuum oil extractor.
3. The oil evacuator tube can be easily pushed all the way to the bottom of the gearbox housing where any fine wear debris (steel) should be.

If you dismantle the gearbox you will see why none the above will work if it's mounted the other way as you suggested.

After pulling the plate it appears that if it was tapped in the center of the plate a screwdriver could be inserted down to the top of the shaft which looks to be about 1/4" below the fill plugs. If it was below that you wouldn't get a measurement but if it was at normal level I would think you would. Couldn't use a vacuum oil extractor in that location though.
Now I think drilling and tapping toward the front of the plate should allow for the oil extractor tube to be pushed to the bottom.

 

[arto98607]

After pulling the plate it appears that if it was tapped in the center of the plate a screwdriver could be inserted down to the top of the shaft which looks to be about 1/4" below the fill plugs. If it was below that you wouldn't get a measurement but if it was at normal level I would think you would. Couldn't use a vacuum oil extractor in that location though.
Now I think drilling and tapping toward the front of the plate should allow for the oil extractor tube to be pushed to the bottom.

Sounds good and I hope it works as you described, however pulling out the two other covers is not much different than pulling this blank cover, except you would need to be careful not to damage the oils seals.

By the way, inside of the gearbox was dirty and disassembling it gave me a good opportunity to inspect the gears & bearings and clean it out, but that's not a big deal.

In other words: I actually wanted to open it up & take a look anyway!

 

[Capt.Ron]

Sounds good and I hope it works as you described, however pulling out the two other covers is not much different than pulling this blank cover, except you would need to be careful not to damage the oils seals.

By the way, inside of the gearbox was dirty and disassembling it gave me a good opportunity to inspect the gears & bearings and clean it out, but that's not a big deal.

In other words: I actually wanted to open it up & take a look anyway!

So I got this thing together. I don't think it's run this smooth since I bought it. The gear box does seem to get a little hot but I never really checked the original gearbox for heat.
Thanks for all of the help!

 

[arto98607]

So I got this thing together. I don't think it's run this smooth since I bought it. The gear box does seem to get a little hot but I never really checked the original gearbox for heat.
Thanks for all of the help!

No problem, glad I was able to help and it's working out well for you!


As mentioned earlier, I did the first oil change after less than one hour of use and have done three more oil changes since.
First one had bunch of fine metal in the removed oil, 95% less in the second and basically none in the third oil.

The gears are pretty rough compared to the Superior gearbox gears, but being rated for 40 hp, I think it will be just fine for this service and I consider it as a temporary low cost spare gearbox.

I switched to synthetic 75W-90 the last time and now have little over 20 hours on use.

Cheers

 

[Capt.Ron]

No problem, glad I was able to help and it's working out well for you!


As mentioned earlier, I did the first oil change after less than one hour of use and have done three more oil changes since.
First one had bunch of fine metal in the removed oil, 95% less in the second and basically none in the third oil.

The gears are pretty rough compared to the Superior gearbox gears, but being rated for 40 hp, I think it will be just fine for this service and I consider it as a temporary low cost spare gearbox.

I switched to synthetic 75W-90 the last time and now have little over 20 hours on use.

Cheers

I know you had said,

"All four bearings in my Superior 211ADF 189 6 Gearbox are just regular conical roller bearings like Timken Set 14 (L44643 / L44610).
It's a common trailer wheel bearing size. The oil seals are TC 1.00 x 1.5 x 0.25 Inch"

Were you able to locate the shafts and gears? I'd like to completely rebuild my old gearbox. The input shaft has wear on it from where the yolk was flopping around. And I'd like to key that shaft instead of slipping the bolt through.

 

[arto98607]

I know you had said,

"All four bearings in my Superior 211ADF 189 6 Gearbox are just regular conical roller bearings like Timken Set 14 (L44643 / L44610).
It's a common trailer wheel bearing size. The oil seals are TC 1.00 x 1.5 x 0.25 Inch"

Were you able to locate the shafts and gears? I'd like to completely rebuild my old gearbox. The input shaft has wear on it from where the yolk was flopping around. And I'd like to key that shaft instead of slipping the bolt through.

1. The gears looked like new in my 3600 hour OEM gearbox.

2. I was able to buy new input shaft for my (Superior 211ADF 189 6) from Messick's but that was all they had for it!

On inspection I realized the input shaft is just a straight 3/4" shaft with two snap ring grooves and two key-ways so it would be a easy to make another one if ever needed, but I am missing a milling machine - no problem there are many local shops able to cut a simple key-way.



There is a difference in the gears in-between the two gearboxes which is why I eventually will re-install the old Superior gearbox, and you may already know all about it but for the benefit of others:

"The advantage of the spiral tooth over the straight tooth is that they engage more gradually. The contact between the teeth starts at one end of the gear and then spreads across the whole tooth. This results in a less abrupt transfer of force when a new pair of teeth come in to play."


Superior gears:

Spinco "straight tooth" gears:

I think either will be fine for a while, but just as a principle I want to go back to the OEM sometime this winter or later.

 

[Capt.Ron]

1. The gears looked like new in my 3600 hour OEM gearbox.

2. I was able to buy new input shaft for my (Superior 211ADF 189 6) from Messick's but that was all they had for it!

On inspection I realized the input shaft is just a straight 3/4" shaft with two snap ring grooves and two key-ways so it would be a easy to make another one if ever needed, but I am missing a milling machine - no problem there are many local shops able to cut a simple key-way.



There is a difference in the gears in-between the two gearboxes which is why I eventually will re-install the old Superior gearbox, and you may already know all about it but for the benefit of others:

"The advantage of the spiral tooth over the straight tooth is that they engage more gradually. The contact between the teeth starts at one end of the gear and then spreads across the whole tooth. This results in a less abrupt transfer of force when a new pair of teeth come in to play."


Superior gears:

View attachment 712726






Spinco "straight tooth" gears:

View attachment 712727

I think either will be fine for a while, but just as a principle I want to go back to the OEM sometime this winter or later.

I haven't opened my old gear box yet but if I turn the input shaft back and forth I can feel a very slight bit of slack. Not sure if it's gear wear or something else.
I'm sure I can get a local machine shop to cut a new shaft. Wonder if those gears could be found through a generic supplier?

 

[arto98607]

I haven't opened my old gear box yet but if I turn the input shaft back and forth I can feel a very slight bit of slack. Not sure if it's gear wear or something else.
I'm sure I can get a local machine shop to cut a new shaft. Wonder if those gears could be found through a generic supplier?

I would not be too concerned about slight slack in the spiral gears at all and in fact any wear (slack) in the conical roller bearings will increase the axial play in the shafts & slack in gears.

Subject to inspecting the gears, hopefully new bearings & seals should be all it needs.
I have not tried to find new gears since they are fine - gear oil change every couple of years should keep them in good shape.

Please keep us posted of what you find out later regarding this?

 

[dieselbob69]

My 1997 F3060 has what I think is somewhat rare RC72R-F30 Rear Discharge Deck and was just recently told by a dealer that Kubota is no longer selling replacement gearbox!

I was just looking to buy a spare gearbox but was unable to find anything offered online by the gearbox supplier either (Superior Gearbox Company, Stockton, MO) - in all fairness I never phoned them since I decided to look for alternatives first since the last Kubota list price for replacment was $631.39 (when it supposedly was still available)!

That's cheap! Look at the price for one of the gearboxes for a RCK BX54/60 deck! Glad I don't need one, cheaper to find a whole used deck on marketplace or craigslist....