# New Holland hydraulics for TN75D FYI



## labdwakin (Jun 21, 2016)

When we started the first cutting of hay, I had used the TN75D for a little bush hogging for pasture maintenance and thought it was good to go for the first cutting.

Well, with about 80 acres of hay laying on the ground, the high pressure hydraulic pump ate itself. Got a new one put on but the hydraulics still didn't work right, the 3 point lift wouldn't lower, the engine lugged unless you were actively moving the front end loader, and after running for just a few minutes the pump was hot enough to fry sausage on!

Did some poking around and ended up removing the remote pod and then the auxiliary control valve. When the pump ate itself it sent massive amounts of aluminum shavings downstream and clogged up the auxiliary control valve and the built in bypass valve that kicks in when you're not actively using the high-pressure hydraulics. Cleaned almost 2 ounces of shredded aluminum out of it and finally was ready to go back to work.

Just thought I'd share this with you guys in case someone else ran into the same problem.


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## r82230 (Mar 1, 2016)

Welcome labdwakin.

Hope nobody needs your info, but it is a good post, just 'in case'.

Larry


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## slowzuki (Mar 8, 2011)

Any time a pump calves you need to clean the whole hydraulic system. It will jam priority valves, prv's anywhere the fluid goes.


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## RuttedField (Apr 24, 2016)

Back when I worked on the railroad there was a machine that was hydraulically driven down the track and it was not properly engineered. It needed some accumulators on it so when it went down hill and got into an overspeed situation it would not cavitate the pumps. Until they figured that out we were forever cleaning the system after the swash plates exploded!

In that job we had two jobs, the one sending the cleaning agent down the hard steel lines, or the one with a 5 gallon bucket capturing it. In other words, you were either the "wad blower", or the "wad catcher". It was the running joke at the time.

It took us 2 weeks to completely clean the hydraulic system out working 6 10 hour days.

There is only one word you need to know when working with hydraulics: CLEAN!


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