Kubota B7100D FEL 4 wheel drive not working

[Mike J Kb5100]

Hello all,
I have recently bought a B7100 with a FEL, The 4 wheel drive hasn't been working since I got it, the guy I bought it off of says that he was using it and then it just didn't work, no grinding no popping just stopped working, it works well with 2 wheel drive but I need to figure out the 4 wheel... I have a service book for it and the only thing that it says is if the shaft to the front diff isn't spinning then its either a 15T or 25T gear I believe. It says its also possible that the shift fork for the 4 wheel have popped out and I'm not even sure how that would work. this is my first 4 wheel drive unit, any suggestions? thanks in advance! Mike.

 

[Roadworthy]

Try to find out how much time has been spent in 4WD while driving on pavement, if any. Besides being rough on tires that can take out the 4WD.

 

[Mike J Kb5100]

Try to find out how much time has been spent in 4WD while driving on pavement, if any. Besides being rough on tires that can take out the 4WD.

Today I was in the shop working on it, so with the back end and the front end jacked up tires off the ground, the front and rears spin when it is engaged and the rears only when in 2wd. I put it in 4 wheel and had the front tires spinning in the air and my buddy just slowly grabbed them and they came to a stop they don’t seem to be working under load. I’m not even sure what would cause that. I was guessing a shaft somewhere having splines wore down or something but I’m not sure.

 

[torch]

Sounds like the shifter fork is ok. When your buddy stopped the wheel, did that also stop the front drive shaft from spinning? That would indicate if the problem was in the front axle or the transmission.

 

[Mike J Kb5100]

Sounds like the shifter fork is ok. When your buddy stopped the wheel, did that also stop the front drive shaft from spinning? That would indicate if the problem was in the front axle or the transmission.

Yes the shaft was still spinning, I looked in the service book and noticed there’s jaw couplers I believe they are called could they be slipping? They are couplers to power the wheels

 

[torch]

It sounds like things are pointing at the front differential or hubs if the front driveshaft continues to rotate when both wheels are stopped. With the engine off, holding the front driveshaft and one wheel at a time while attempting to rotate the other wheel might point to which side has the problem.

The good news is that it is easier to remove and disassemble the front axle assembly than to split the tractor and disassemble the transmission. The bad news is that is where I think you are headed.

 

[Mike J Kb5100]

It sounds like things are pointing at the front differential or hubs if the front driveshaft continues to rotate when both wheels are stopped. With the engine off, holding the front driveshaft and one wheel at a time while attempting to rotate the other wheel might point to which side has the problem.

The good news is that it is easier to remove and disassemble the front axle assembly than to split the tractor and disassemble the transmission. The bad news is that is where I think you are headed.

I’ll keep digging into it tonight, it looked fairly simple to do, thank you! I’ll keep you updated!

 

[Mike J Kb5100]

I’ll keep digging into it tonight, it looked fairly simple to do, thank you! I’ll keep you updated!

Alright so I found the issue to looks like the previous owner jammed it into 4wd while moving to fast or something because I found all 6 bolts that bolt the gear off the input shaft had been snapped and the heads lying in the oil, now I’ll have to take it apart and drop the diff and drill the studs out

 

[torch]

Could be much worse -- could need new gears or something. Parts are getting harder to find for these old gems. I bet the bolts wind out easily -- especially if you use a left-hand drill bit.

 

[Lencho]

Can you post a photo of the sheared bolts? I am trying to picture where the weak point was.

 

[Mike J Kb5100]

I’ll post a picture here in a little bit, that’s the only thing I can think of because I couldn’t picture them snapping in any other way it looks like there was a lot of torque on them

 

[Mike J Kb5100]

I’ll post a picture here in a little bit, that’s the only thing I can think of because I couldn’t picture them snapping in any other way it looks like there was a lot of torque on them

Can you post a photo of the sheared bolts? I am trying to picture where the weak point was.

 

[torch]

Hard to be sure from those pictures, but it looks to me like those bolts were overtightened rather than sheared. The fractures look concentric rather than pinched.

 

[Mike J Kb5100]

Here are some pictures

 

[Mike J Kb5100]

Here are some pictures

Didn’t realize I already sent them Lol, the teeth on the king gear there have a burr on them I need to remove but other then that they should be alright