Kubota L3430 Hydraulic Pump Noise

[CobraTom]

Good day everyone,
I have a L3430 that I split and replaced the motor with a rebuild.
Everything is back together now and running but I am getting some hydraulic pump noise

Any suggestions outside of the obvious?

The HST and Hydraulic filters have been replaced, new Premium UDT oil, HST runs great and less noise with new fluid and filter, but the hydraulic side is running loud.

 

[rentthis]

Check to see if your 3 point hitch lever is pulled all the way up. The hydraulics might be dead headed.

 

[North Idaho Wolfman]

Rentthis has a good suggestion to check, also a maladjusted feedback linkage can do it.

Also when someone says they have done a split and now it's loud, it's either deadheading or sucking air into the pump.

Check all the suction side lines, hoses, fittings, and seals for seeping leaks when it's not running.
Also check the gauge window or dipstick and see if the fluid is foaming.

 

[CobraTom]

There are no leaks or dead headed connections, I have run all hydraulic functions. It very much sounds like it is the forward portion of the pump which is the power steering circuit

 

[North Idaho Wolfman]

There are no leaks or dead headed connections, I have run all hydraulic functions. It very much sounds like it is the forward portion of the pump which is the power steering circuit

It's very likely your not going to see a suction side leak.

There could be debri in a part of the system causing the restriction and noise.

 

[CobraTom]

So the noise continues after using the tractor since the split.
I have verified the main intake for the hydraulic pump is attached firmly, and replaced the Oil cooler/Power steering return line o-ring.
What is interesting is as soon as I undid the oil cooler return line, I heard a large amount of air rush past, so a vacuum was being created.
Power steering is not affected, but it appears I am either not getting flow from the HST transmission return (that leads to the oil cooler) or the oil cooler itself is clogged.

Next step will be to bypass the oil cooler and see what happens...

 

[North Idaho Wolfman]

Have you checked the relief valve?

 

[CobraTom]

Have you checked the relief valve?

Can you explain that a bit further? I am not sure how a relief valve would lead to no flow through the oil cooler? If anything it would increase flow through the oil cooler?