Loud clunking when engine starts

[Christian Babirad]

We have a Kubota TG1860 diesel tractor that has been in the family since brand new. I recently inherited it without the deck on. When I start the tractor a really loud clunking noise is coming from under the tractor no matter the rpm, and The pto does not work at all. I got my girlfriend to start it while I looked what was happening under the tractor and the u joint infront of the pto box is wobbling everywhere so I got her to turn it off and I felt the u joint/the shaft where it goes into the pto box has about a 1/4” play in it I also noticed the flex coupling is also quite worn out so I’m guessing it is the flex coupling. Does anyone think it could be something else?

 

[Christian Babirad]

The tractor moves in forward and reverse perfectly fine just with a loud clunking noise

 

[cthomas]

That flex coupling is missing a bolt it looks like. Need a picture of the ujoint.

 

[Christian Babirad]

That flex coupling is missing a bolt it looks like. Need a picture of the ujoint.

I took the one bolt off already. Here’s a pic of the u joint and the second pic is the shaft that goes into the pto box and that shaft has about a 1/4 play side to side in it

 

[Trimley]

Now you know why, you inherited it. 🫤

It will likely need some maintenance.

 

[Christian Babirad]

These are the pictures

 

[Christian Babirad]

Now you know why, you inherited it. 🫤

It will likely need some maintenance.

Yeah lol they gave it to me because they were having this issue and were going to throw it away. The engine is fine and it drives fine it just has that bad noise I’m trying to figure out how to fix it

 

[Workerbee]

On your last pictures, is the 1/4” play in the u joint knuckle? Or in the splined shaft? If the u joint, simply get a new one and change it. If its the splined shaft, theres a bearing out, likely right behind that seal you see around the shaft. You likely will have to disassemble that gearbox to replace it. Unless you can get it out the front somehow.

 

[jaxs]

Diagnosing problems from looking at pictures is somewhat a fool's game but I see metal shavings that likly came from the u-joint spider so my money is on worn out u-joint.

 

[cthomas]

If you can remove the shaft and start the engine is the noise gone?

 

[Christian Babirad]

On your last pictures, is the 1/4” play in the u joint knuckle? Or in the splined shaft? If the u joint, simply get a new one and change it. If its the splined shaft, theres a bearing out, likely right behind that seal you see around the shaft. You likely will have to disassemble that gearbox to replace it. Unless you can get it out the front somehow.

The 1/4” play is in the spindle shaft. I removed the whole gear case to better access it and the shaft on the gear case that the drive shaft connects to has a 1/4” play side to side

 

[Christian Babirad]

Diagnosing problems from looking at pictures is somewhat a fool's game but I see metal shavings that likly came from the u-joint spider so my money is on worn out u-joint.

Yes there was some metal shavings there but the u joint was spinning off center due to the gear box shaft bearing being out so I will probably have to place the u joint too

 

[Christian Babirad]

If you can remove the shaft and start the engine is the noise gone?

I wasnt sure if I can start the engine without the driveshaft connected. I’m completely new to all this so I’m not sure about anything really that’s why I came to here, I just wasn’t sure if I should start the engine without any load on it

 

[fried1765]

I wasnt sure if I can start the engine without the driveshaft connected. I’m completely new to all this so I’m not sure about anything really that’s why I came to here, I just wasn’t sure if I should start the engine without any load on it

You have a very thoughtful approach!

 

[Christian Babirad]

You have a very thoughtful approach!

Thanks!