B7100 open front diff?

Lil Foot

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1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
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Settle an argument for us. I have a neighbor who insists that all Kubota 4wd front differentials are locked- I say they're open, or they wouldn't steer, they'd tend to pull straight ahead. While I was grading in a ditch & then climbing out on a pretty severe angle, he noticed one front wheel was not always pulling, & said I must have a broken axle. Parts diagram certainly looks like an open diff...
 

MagKarl

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L245DT
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You're spot on LF, open diffs up front. They both pull when they have traction. Look at the size of the arcs that the fronts travel, huge difference in path length.
 

North Idaho Wolfman

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Settle an argument for us. I have a neighbor who insists that all Kubota 4wd front differentials are locked
Well you are both wrong! :eek:

Some have open diffs and some have lockable diffs, Yes all the B7100's have open diffs as do almost all of the older Kubota's.
So yes a tire that has more traction will get less power applied to it, so the tire without traction will spin, that normal. ;)
Newer and larger Kubota's can have a lockable diff, so with those you can lock the wheels together and both tires will get equal pulling power. :D
It's a nice system, but comes at a cost, they must either auto or be manually kicked off on a turn or they will not turn properly, and they wear tires at a greater rate. :cool:
 

hodge

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Well you are both wrong! :eek:

Some have open diffs and some have lockable diffs, Yes all the B7100's have open diffs as do almost all of the older Kubota's.
So yes a tire that has more traction will get less power applied to it, so the tire without traction will spin, that normal. ;)
Newer and larger Kubota's can have a lockable diff, so with those you can lock the wheels together and both tires will get equal pulling power. :D
It's a nice system, but comes at a cost, they must either auto or be manually kicked off on a turn or they will not turn properly, and they wear tires at a greater rate. :cool:
They are still open differentials; just some are also lockable.

Lilfoot- tell your neighbor to jack up the front of his tractor, and spin one wheel. If the other rotates the opposite direction, it is open. If the other tire spins the same direction, it's locked.
All 7100's are open.

Your neighbor may have, at some point, seen both front tires spinning. When traction is equal on both sides, both tires will pull- an open differential can spin both tires. When traction is unequal, which happens the majority of the time, then power will differentiate to the side with less resistance.

If tractors came with spooled or locked front differentials, they would be very difficult to turn, whether in 4WD or not.
 
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Lil Foot

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1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
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Thanks for the confirmation gentlemen! I'm going to enjoy my victory suds!:D
 

Dave_eng

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My M7040 has a limited slip front dif. It leaves me wanting a way to physically lock it at times but is is certainly better than an open one.
Dave M7040