TG1860 diesel

[Dave_eng]

Tomorrow I have been asked by a friend for help with his TG1860 diesel.

He has been experiencing a strong vibration with only the motor running and has concluded something is amiss in the driveshaft from the engine to the bevel gear box at the rear of the tractor.

He says he has the driveshaft loose at the motor end but cannot figure out how to pull the shaft from under the machine. The mower deck is still in place. The engine end of the shaft is a circular piece (#410) and seems to big to slide out.

Any advice on driveshaft removal on this model would be appreciated.

Dave

 

[D2Cat]

Dave, might send a PM to whitetiger.....he would know for sure. I'd just be guessing!!

 

[Dave_eng]

Dave, might send a PM to whitetiger.....he would know for sure. I'd just be guessing!!

Thanks
I will go and see for myself today and if its not obvious then follow your suggestion.

Any idea why this model's engine seems to be in backwards..... flywheel at the front bumper. Must be a good reason that escapes me.

Dave

 

[Dave_eng]

I thought I should share this info for the next TG1860 owner.

My friend had found the flex coupling bolts in the middle of the driveshaft from the engine to a bevel gear box at the rear loose and had struggled to tighten then with everything in place.

My observation, and one that worked well, was to remove the rear fenders, seat, floor pan and fuel tank as a complete unit. This took about 30 minutes and greatly opened up access.

The flex coupling looked damaged and my friend had over tightened the bolts. I have posted before about the springs used in clutch disks as a way to absorb the torsional vibrations the diesel engine sends into the drive line.

In the TG1860 layout where the main power is taken from the non flywheel end of the engine, I suspect these two flex disks are put in the middle of the shaft to also absorb torsional engine firing vibrations.

The two rubber disks and bolts come as a unit costing $240 in Canada

Dave

 

[kubotafreak]

Dave,

You dont picture the yoke ends. Is the drive line phased right. Yoke ear to ear in line with shaft? Would be more reason for the vibration than the rag joint...

 

[Russell King]

Are there supposed to be washers underneath the nuts? What are the spacers between the rubber supposed to accomplish? Reduce some friction and wear maybe?

Just looks like it is assembled incorrectly and the nuts will tear through the rubber eventually. But I have never seen the assembly before so don’t really know.

 

[Dave_eng]

Dave,

You dont picture the yoke ends. Is the drive line phased right. Yoke ear to ear in line with shaft? Would be more reason for the vibration than the rag joint...

To start, this machine was bought brand new by my friend and the driveshaft never touched until the rapid increase in vibration with the mower off so there is no drive joint phasing issues.

I will post more photos to ally your concerns. I expect when the new "rag joint" arrives we will find its geometry is twigged to prevent out of phase assembly.

Drive line joint phasing comes into play when the joints are operating at an angle. On the TG1860 the shaft and joints have no angularity so even if the joints were not phased I would not expect any vibration.

Thanks for your comments.

Dave

 

[Dave_eng]

Are there supposed to be washers underneath the nuts? What are the spacers between the rubber supposed to accomplish? Reduce some friction and wear maybe?

Just looks like it is assembled incorrectly and the nuts will tear through the rubber eventually. But I have never seen the assembly before so don’t really know.

Russell

When the new parts arrive I will post some photos before assembly. Because the disks and nuts and bolts are shown as one unit, it is not possible to see a disassembled view in the parts illustrations.

I do not know what parts my friend may have added hoping to fix the floppy condition of the joint. The current condition in my photo likely does not represent the assembly line condition. I expect to find metal sleeves the length of the disk thickness on each bolt to prevent compression of the flex disks.

The images in the WSM are not very good so discerning detail is difficult.

Dave

 

[Russell King]

Russell

When the new parts arrive I will post some photos before assembly. ...

Dave

Thanks.

 

[whitetiger]

My observation, and one that worked well, was to remove the rear fenders, seat, floor pan and fuel tank as a complete unit. This took about 30 minutes and greatly opened up access.

Dave, Life is too short to try to work on one without removing the sheet metal. Your observation was spot on!!

 

[Dave_eng]

Dave, Life is too short to try to work on one without removing the sheet metal. Your observation was spot on!!

Do you have to remove the sheet metal even to grease the three fittings on the shaft?

Daave

 

[kubotafreak]

 

[xrocketengineer]

Thanks
I will go and see for myself today and if its not obvious then follow your suggestion.

Any idea why this model's engine seems to be in backwards..... flywheel at the front bumper. Must be a good reason that escapes me.

Dave

All the BX's are that way too. I am not a tractor expert but if I remember well one of the Messick's videos, Neil points out that is better for mowing (no grass blades clogging the grill/radiator) and by sucking the air for the radiator from the floor board area, keeps the rider cooler and the radiator and air filter cleaner.

 

[lugbolt]

you might be wise to check the slip yoke/spline connection at the rear for play. It should slip onto the shaft tightly. If it has any slack side-to-side it'll vibrate.

yes the TG1860 used a torsional vibration dampener (aka rag joint). Poor excuse for a harmonic dampener but it's what we have to work with. They should have used a guibo at the engine. Automotive manufacturers often use a guibo at the back of the transmission. My Mustang has one. I'm not excited about it but it's there and it reduces (greatly) felt vibration from the little 4 cylinder engine when the torque converter is locked and rpm is low. This allows manufacturer to "lug" the engine resulting in better mpg and greatly reduced nvh. My other car (also a 4 cyl Mustang although much older) doesn't have one and it's real brash below 1400 RPM.

all of the G series diesels didn't have any sort of harmonic dampener and it was pretty common for them to wear out splined couplings and especially u-joints. Yes, remove engine to get the shaft out (easier than pulling the steering and floor).

lots of reasons the engine is in there backwards, one being that it allows a shorter hoodline, for much better aesthetics and more importantly better visibility over the nose of the tractor. With the radiator out front the hood will be longer and taller, and look different. Some of it has to do with marketing. Who wants to buy an ugly tractor?

with the coupling in the center of the shaft like that, when the material weakens the shaft assembly tends to whip. This causes some of the felt vibration and can usually also be seen, with the deck off of course.

 

[whitetiger]

Do you have to remove the sheet metal even to grease the three fittings on the shaft?

Daave

No, you do not have to, but it's probably about as quick if your not a contortionist or you don't have a lift to put it on.
After you have removed the sheet metal a couple of times, it only takes about 10 minutes and then everything is out in the open. Far simpler and easier than the alternative.
They are a very popular and trouble-free mower, I only remember replacing one rag joint in them and we have lots of them running around with 2500 to 4000 hours on them. Some are just used now to pull carts around the farm with as the decks have worn through and were thrown away.

 

[Dave_eng]

No, you do not have to, but it's probably about as quick if your not a contortionist or you don't have a lift to put it on.
After you have removed the sheet metal a couple of times, it only takes about 10 minutes and then everything is out in the open. Far simpler and easier than the alternative.
They are a very popular and trouble-free mower, I only remember replacing one rag joint in them and we have lots of them running around with 2500 to 4000 hours on them. Some are just used now to pull carts around the farm with as the decks have worn through and were thrown away.

Thanks Whitetiger
My friend has a lift but old arthritic hands made greasing almost impossible.

We will drill removing the sheet metal until we are like the Formula 1 pit crews.

Dave

 

[Dave_eng]

Photos of worn flex joint parts supplied to Kubota by Wexler Engineering.

Note the three oval holes from absorbing torque pulses.

New joint assembled according to Wexler instructions see attached file. Fig 2 is the TG1860 one. Note through bolts are SAE not metric.

Rolled washers cut into surface of heavy washer in middle of flex joint.

To reinstall assembled pto shaft it was easier to loosen bolts holding steering wheel and rad area to get shaft into place.

Dave

 

[Russell King]

Dave,
Thanks for posting the pictures of the new assembly

 

[Christian Babirad]

Tomorrow I have been asked by a friend for help with his TG1860 diesel.

He has been experiencing a strong vibration with only the motor running and has concluded something is amiss in the driveshaft from the engine to the bevel gear box at the rear of the tractor.

He says he has the driveshaft loose at the motor end but cannot figure out how to pull the shaft from under the machine. The mower deck is still in place. The engine end of the shaft is a circular piece (#410) and seems to big to slide out.

Any advice on driveshaft removal on this model would be appreciated.

View attachment 61882

Dave

Did you have to pull the engine to pull the driveshaft? And was the rattle when just the engine was on and not the pto? I’m having an issue right now where when I start the engine a loud rattling noise comes on no matter the rpm and the pto doesn’t even work at all. I looked under the tractor when it was idling and the u joint infront of the pto box was rattling a lot and the flex coupling is pretty worn I’m just wondering if it is just the flex coupling i need to replace

 

[Dave_eng]

Did you have to pull the engine to pull the driveshaft? And was the rattle when just the engine was on and not the pto? I’m having an issue right now where when I start the engine a loud rattling noise comes on no matter the rpm and the pto doesn’t even work at all. I looked under the tractor when it was idling and the u joint infront of the pto box was rattling a lot and the flex coupling is pretty worn I’m just wondering if it is just the flex coupling i need to replace

No need to pull the engine.
With a little head scratching the body work can come off making access a lot easier.
From memory, the front half and the rear half are sepatate
Replace the coupling and likely the other issues will be solved
Dave