Front locked up?

[Ric]

L4240 HST
I was not on the machine but this is what I know so far-
Driving on hard surface to transport about 1/2 mile with front axle engaged (first problem) the wheels locked up. I show up, put it into 2 WD and tractor moves again. In 4 wheel drive machine tries to move (can tell engine strain) but will not. Get to a safe spot in 2 wheel drive and now have to figure out what is frozen. Hoping that it is something in the front axle but since it still turns I'm kind of skeptical of it being that simple. Dreading that it is something locked up in the 4 wheel drive section of the transmission.

Any shot in the dark ideas? I know diagnosing over the internet is not easy but tomorrow I will be seeing what I can find.
-Rich

 

[100 td]

Jack the front if you can and turn everything to ensure there is nothing dragging/crunching in the front. You may have a failure in the box, I haven't/won't have time to look at the manual, plenty of folks here will chime in with knowledge. A WSM online if you don't have one.
http://www.kubota.cz/data/soubor/WSM_L3540_4240_5040_5240_5740_EN.pdf

 

[Lil Foot]

The front axle of my B7100 locked up during 4wd use, and turned out to be a torn up gear set & bearing left over from some PO screwup & poor repair.
http://www.orangetractortalks.com/forums/showthread.php?t=21369&highlight=found

But this also sounds like a problem an acquaintance had on a Jeep transfer case/transmission. Don't remember the exact details, but I remember it had been driven in a tight circle on dry pavement with 4wd & the hubs engaged, & then it locked up. It was found that a gear (or maybe a shaft?) had been slid out of place by the strain, and it was actually engaged in two gears at the same time, locking it solid.

 

[rbargeron]

L4240 HST
........... Hoping that it is something in the front axle but since it still turns I'm kind of skeptical of it being that simple. Dreading that it is something locked up in the 4 wheel drive section of the transmission........

Problem could be anywhere - sometimes a failed system will roll ok under near-zero torque, but locks up when there is any force in the parts. 100TD's advice is good - jack it up and see what's what.

 

[Ric]

So had a few min to look at the tractor today after the snow. Lifting the front axle off the ground with the FEL and moving forward or reverse the tires are spinning with no unusual noise. Driving with all wheels on the ground in 2 or 4 all wheels go around but pushing into a pile there is no torque spinning the front wheels (the rear wheels slip, front do not). I did not get to remove any covers on the front prop shaft yet but I am starting to think something like a woodruff key or something is sheared or some issue with the 2wd/4wd lever/gear.

 

[100 td]

...but I am starting to think something like a woodruff key or something is sheared or some issue with the 2wd/4wd lever/gear.

Here's hoping it's only a key, unfortunately I wouldn't be so lucky, I hope you are!

 

[lugbolt]

There is a drive shaft that runs between the oil pan. Remove it and look at the splines on the front axle pinion. Also look at the splines on the collars.

 

[mikester]

L4240 HST
I was not on the machine but this is what I know so far-
Driving on hard surface to transport about 1/2 mile with front axle engaged (first problem) the wheels locked up. I show up, put it into 2 WD and tractor moves again. In 4 wheel drive machine tries to move (can tell engine strain) but will not. Get to a safe spot in 2 wheel drive and now have to figure out what is frozen. Hoping that it is something in the front axle but since it still turns I'm kind of skeptical of it being that simple. Dreading that it is something locked up in the 4 wheel drive section of the transmission.

Any shot in the dark ideas? I know diagnosing over the internet is not easy but tomorrow I will be seeing what I can find.
-Rich

Broken front diff ring gear and pinion. You've got little bits of metal floating around in the front diff case. Don't drive it unless you want even more expensive repairs.

 

[North Idaho Wolfman]

What you are describing sounds like a final drive or possible a differential issue and not a drive shaft issue.

Remove drive shaft front cover, jack up only one wheel and turn wheel while watching shaft rotation and feeling for grinding, clicking, snapping or any resistance, should be super smooth.
do the same to the other wheel.
Then do both drive shaft should stay relatively stationary and other wheel should spin opposite direction freely.

 

[Ric]

Got it up on a lift this afternoon and slipped back the prop shaft cover. turning both wheels in the same direction I can feel some crunches and the shaft is not turning. Turn the shaft and I can feel some intermittent resistance when the wheels move, definitely not smoothly. Will have to dig a bit deeper into the front axle and see what went crunch.

 

[Ric]

Back at the shop today and think I have found the problem





Now to go look in the book to see how to get it apart

 

[mikester]

Back at the shop today and think I have found the problem

View attachment 35213

View attachment 35211

Now to go look in the book to see how to get it apart

Ouch. Be glad its a Kubota. NH parts are gold plated, dealer only and priced accordingly.

It's probably going to be a lot easier to remove the complete axel.

 

[Ric]

Started looking already. Ring and pinion set is about $500

 

[Ric]

Got the old pinion out, now have to separate it to get the collar between the bearings off. Also have to remove the diff to change the bevel gear and clean everything up. Should the diff just fall out or will it need some persuasion? Also when assembling the pinion and bearings, what is the best way to keep the assembly from turning so the nut can be tightened?

 

[mikester]

Got the old pinion out, now have to separate it to get the collar between the bearings off. Also have to remove the diff to change the bevel gear and clean everything up. Should the diff just fall out or will it need some persuasion? Also when assembling the pinion and bearings, what is the best way to keep the assembly from turning so the nut can be tightened?

The diff case should come off pretty easy. I let the dealer re-assemble my ring and pinion in the case as they have to shim and torque everything appropriately. I had them replace all the bearings and seals at the same time as it's cheap insurance. The parts for my NH was $2400 be glad Kubota is more reasonable on parts!