L3750 DT random loud continuous mettalic noise. Noise goes away after restart

[plabane]

Hello everyone, first post here.

I have owned a 1986 L3750 DT shuttle shift w/ loader and box for approximately 8 months. Unknown hours (meter doesn't work). Tractor works great and was serviced when I purchased it. Engine and hydraulic fluid are full.

When the tractor is running, PTO off, it will occasionally make a very loud, continuous, metallic scraping/rattle noise and vibration that sounds like the part/parts causing the noise are turning at speeds at or near engine RPM.

When I push the clutch in, the issue sometimes stops. If I turn the engine off and restart, the issue goes away. When it is at operating temperature or above idle, the issue occurs more often. Hydraulics and forward/reverse still work when the problem is occurring.

The best way I can describe the noise is like having a South Bend Dual Disk clutch and pushing the clutch in (metallic scraping/rattle). The vibration and feel of it is like a washing machine that is improperly loaded and off balance.

When I turn the engine off, noise slows down and finally stops like it is spinning at same revolution as engine.

Seems to be clutch related but tractor still moves fine when the issue is occurring. I am unaware how these tractor clutches work compared to other vehicles but would it be possible the clutch can come off balance and just resets itself when the tractor is turned off?

It was suggested to me that it could be a hydraulic pump issue, but, hydraulics and tractor still move when the issue is occurring.

Tractor still works great but noise is extremely loud and something has to be coming apart or working towards a catastrophic failure.

As of writing this, I realized I have not attempted to see if the issue occurs when the PTO is activated. I will try to video the issue occurring when I get back out to the property.

Any advice or suggestions is greatly appreciated.

Paul

 

[North Idaho Wolfman]

Could be the clutch disks are coming apart, but way more likely that the throw out bearing is going out or is out, fix it now or it will cause more issues.

 

[plabane]

Thank you for the reply, Wolfman. I can see the clutch and it's components being the cause of the issue.

Have you ever heard of a hydraulic pump intermittently making a continuous loud metallic noise until the tractor is shut off, then normal on restart?

When I split the tractor to replace the clutch and it's components, would you recommend replacing or addressing anything else? I don't want to shotgun parts at it but if it could save me several hours of trial and error, may be something to consider.

Thank you all for your time.

 

[North Idaho Wolfman]

Thank you for the reply, Wolfman. I can see the clutch and it's components being the cause of the issue.

Have you ever heard of a hydraulic pump intermittently making a continuous loud metallic noise until the tractor is shut off, then normal on restart?

When I split the tractor to replace the clutch and it's components, would you recommend replacing or addressing anything else? I don't want to shotgun parts at it but if it could save me several hours of trial and error, may be something to consider.

Thank you all for your time.

Yes you would be right that a failing hydraulic pump could possibly make that noise, but pushing the clutch in would have no effect on it as it's attached to the side of the engine and driven off the fuel cam.

Also if it was making that much noise, you would have no hydraulic ever!

Any split I do, I count on pilot bearing/ bushing, clutch plate pressure plate and throwout bearing.
If there is any oil or hydraulic fluid in the bellhousing upon splitting it then address that too, it's rare to have to do any seals though.

 

[eserv]

Yes you would be right that a failing hydraulic pump could possibly make that noise, but pushing the clutch in would have no effect on it as it's attached to the side of the engine and driven off the fuel cam.

Also if it was making that much noise, you would have no hydraulic ever!

Any split I do, I count on pilot bearing/ bushing, clutch plate pressure plate and throwout bearing.
If there is any oil or hydraulic fluid in the bellhousing upon splitting it then address that too, it's rare to have to do any seals though.

Could it be the starter failing to disengage?

 

[North Idaho Wolfman]

Could it be the starter failing to disengage?

You know you're right it could, but I'm still thinking that because he can get the noise to quit when he pushes the clutch in, it's still a better bet thinking throwout bearing, but pull the starter first just to make sure.