M9540 HD12 steering issues

[SSweet9c1]

Hey I have an 07 M9540HD12 I bought it used two years ago, around 2200 hours, it was not treated well at the pig farm it lived on in western Ohio, But I use it for pulling a 4X16 rollover plow, 13' soil perfecta 2large lime spreader etc.
So far it has been a good tractor, i got a **** of a deal on it (so I've been waiting for something big to go wrong)
The other day after spreading 38 tons of turkey manure with a large lime spreader, the steering started acting funny.. If I let go of the wheel (driving or sitting still) the wheel will turn all the way to the lock in whatever the last direction you turned it in was..
IE If I stop the tractor, and let go of the wheel, it will just start turning all the way to the right or left...
thanks
Jonathan

 

[Tx Jim]

Sounds as if steering valve component has failed. A seal kit is offered so I think one needs to look inside valve body for worn/broken parts.

 

[big bubba]

good advice. at same time of addressing above recommendation, might look into replacing hyd fluid/filter (kubota udt should do fine) while you're at it. esp if previously neglected.
the Mxx40 series is excellent