Kubota B600 4wd

[Oldie68]

Needing some help with this. 4wd seemed to be working when I got this li'l beast. Now it definitely is not. Pto shaft coming from transmission turning up to the front differential shaft, splines on shafts although worn a bit are good, when I disconnected shaft and or before I could turn each front wheel independently, with shaft removed from front diff I could turn pto shaft in front diff with no noise or restriction/resistance.
Dunno what could have broken but I'm quite sure it's in the front diff. Information offered would be appreciated. Think it's a 73-75 but its a grey tractor.
Thx.

 

[Carl_NH]

Your description is not clear in the third sentence/statement. If you can post pictures that helps too.

Bottom line, if the front wheel drive is turning from the transfer case to the front drive- great. Rule that out. Second, you say you disconnected this front shaft and the front wheels turn easily - no binding?

If you jack up the front wheels and turn the L or R tire, does the other side go in reverse of that? is there any binding or loose movement in each axle?

 

[Oldie68]

Hi sorry let me attempt to be clearer. I first lifted the front wheels (actually all of them engine running put it it gear in 4wd, only right rear was turning nothing at the front wheels, could turn either front wheel in either direction no resistance and no alternate action from the opposite side. I've shut the machine off still in gear and in 4wd, rotated either front wheel again no resistance and or action from the opposite side. When machine running in gear and 4wd pto shaft from the transmission is turning up to the pinion shaft of the front differential. I removed pto shaft at the U joint at the front differential/pinion shaft I can turn pinion shaft with no resistance, grinding or any sound and still no action at the front wheels. Hope this is clearer.

 

[Carl_NH]

Clearer - sum and substance the front wheels aren't turning with FWD engaged and you have confirmed a functional transfer of power to the front axle.

- Front Pinon Drive Does Turn so the transfer case is delivering / driving the shaft up to the front axle
- Front Wheels (with 4WD disengaged) do not turn the opposite wheel when one wheel is turned

This likely indicates the center ring and pinion gear inside the center front differential is stripped.

Remove the front wheels and and axle - here is a B6000 part list view From Messicks - yours should be close or similar Kubota B6000 (Hydrostatic Transmission, 4wd) Parts

 

[Oldie68]

Your description is not clear in the third sentence/statement. If you can post pictures that helps too.

Bottom line, if the front wheel drive is turning from the transfer case to the front drive- great. Rule that out. Second, you say you disconnected this front shaft and the front wheels turn easily - no binding?

If you jack up the front wheels and turn the L or R tire, does the other side go in reverse of that? is there any binding or loose movement in each axle?

I've edited the original post fro Sept 2022 to include some pictures.

 

[Oldie68]

Clearer - sum and substance the front wheels aren't turning with FWD engaged and you have confirmed a functional transfer of power to the front axle.

- Front Pinon Drive Does Turn so the transfer case is delivering / driving the shaft up to the front axle
- Front Wheels (with 4WD disengaged) do not turn the opposite wheel when one wheel is turned

This likely indicates the center ring and pinion gear inside the center front differential is stripped.

Remove the front wheels and and axle - here is a B6000 part list view From Messicks - yours should be close or similar Kubota B6000 (Hydrostatic Transmission, 4wd) Parts

I've edited the original post from Sept 2022 to include some pictures. I'm thinkin the problem lies at the pinion shaft in the front differential. I'm gonna have a boo here soon and investigate via removing front wheel drive shaft and then remove the three bolts holding the pinion shaft in and see if that's the trouble and whether i can see anything inside differential from there.

 

[ptsg]

Have you checked the U joint near the front diff?

I had a B7000 a couple years ago and it stripped the splines in the U joint near the front diff. Provably caused by the previous owner running 4x4 all the time, specially on hard surfaces.

It wore out the splines so thin that eventually it wasn't even transferring power to the front axle anymore. Hard to see on the picture, but you can see the diferences between the old and new u-joint.

 

[Oldie68]

Yes I've disconnected the shaft to the front differential and the shaft from the transmission to the front differential U joint is fine its from the differential pinion shaft inward to the front differential therein seems to be the problem. Turn the pinion shaft by hand turns freely no resistance, however turing the right front wheel (wheels off the ground) the pinion shaft turns but I can hold the shaft abd turn the wheel and still nothing. Is there any shear pin from the pinion spline to the differential crown gear that could have sheared?