hello! i have a ih 606 with factory backhoe and loader also forward reverser... it is a great tractor i have had it for a 10 years now i have done all the filters and changed the hydro fluid.. it steers ok but when just sitting and running something in the steering is making a sound like a car when you turn to one side and hold it like a loud humming noise.. when you put a little pressure on it it stops making the noise... i looked at the blow up of parts and could not figure what the trouble was also looked at the IT manual had a few tests but nothing seemed like the trouble i am having... pretty sure the pressure comes from the main tractor pump i mention that because there was water getting in the hydro which i fixed since and changed the fluid over a year ago so i would think if there was water in there it should have purged through the system i think.. maybe water trapped in part of the system i wanted to bleed a few lines but figure i would try here first... thanks for any help.... oldvettes

I would just simply put a gauge in the plug at the main pump. You have two pumps. Main one is for power steering first, aux valves second. Small second pump is hitch and then that fluid joins first pump flow at aux valves when hitch is not being raised. Any pressure in neutral should be well below pressure when turning steering wheel. If not, go into flow divider first looking for orfice missing or turned in slot or sticking spool.

thanks for the reply.. i spent some time with the tractor and found the noise was coming from the pump area and the power steering was what i did to make the noise stop and when i use hoe or bucket it also stops or changes tune. so checking pressure at the plug between the lines should tell me if it is pump trouble or flow divider issue? my bucket and hoe work pretty good (or as good as a 1963 tractor can) but if there was flow divider problem it could work better if repaired maybe ? ... chris

i went through similar problems with my 606 when the hydraulics would get good and warmed up. i removed the flow divider valve pilot control valve and cooler pressure regulator valve and gave them all a good cleaning. yes i had some water crap residue in all of them.

thanks for the reply... did it help the trouble you were having?

My 340 IH does that too, when it's running not doing anything it sounds like it lifting. when u do lift the bucket, it runs easier !!!

Your 340 has a totally different hydraulic system than a 606. Yours is staying on pressure due to regulator valve not unseating the unloading valve. This is usually caused by a plugged orfice screen in regulator valve assembly but can be caused by aux valves turned too far toward single or double position with bent or broken roll pin. If it has teledepth hitch that valve can cause the problem also due to totally out of adjustment or wear in valve causing excessive leakage in the regulated circuit. That is when we drill out the orfice to overcome the excessive leakge.

what do you mean it runs easier when lifting the bucket.. it sounds like a different problem....

Oldvettes and Fast. I'm no expert on these hydraulic systems but I can hopefully explain the basis of your issues. IH used a pilot valve system on these open center hydraulics. Essentially the fluid being pumped by the hydraulic pump is circulating under a lower pressure. When a flow demand is placed on the system such as operating a remote valve the pilot valve senses that and then the flow out of the pump is raised up to working pressure until the flow demand is discontinued. At that point the pilot valve sees a spike in pressure and reverts back to low pressure circulation mode. In the case of the 340 the pilot valve is not dropping back to low pressure thus the engine labors under the load of the hydraulic pump. And now after re-reading the OP I'm not sure if this addresses his issue. I'm not certain if the power steering "priority" valve and pilot valve are the same or in the same location in a 606. I think the steering runs off the MCV pump in that tractor so the pilot valve does not apply to that system. So to the OP I suppose my post is really not much help.