Farmall 706 with MCV or TA problems - TRACTOR VET and others

andy r

Member
My IH 706 is mostly a chore/pto tractor so I have not been pressed to fix this issue. But, would like to get it working as it should again. While running an auger in the fall of 2017 I noticed the red light was glowing on the dash. Knowing the light monitored the MCV and engine oil pressure I affirmed that it was an MCV problem by trying the steering and brakes. Sure enough, no steering or brakes. I just thought it had lost its prime. I did over fill the transmission case, blew air into the transmission case and changed the filters. That did not fix the issue, but driving it around slowly it finally took and worked fine. Well, it lost it's prime again on the auger that fall and I could not get it to work again. I just figured a weak MCV pump. So, I put a new Hy Capacity MCV pump in it. Also put new springs into the MCV valve body. Now I have great power steering and brakes, but no TA in direct drive (TA forward). Also when you are on the road it will coast down hill (TA not holding it back). So, new MCV pump and reworked MCV = always working good steering and brakes, but non functioning TA. I thought the TA was working just fine before I had it on the auger that fall. In fact I pulled the auger five miles to that farm with the tractor. I honestly can't remember if I was in direct with the TA. How could the TA go from being good to failing without really doing any work? Anyway now it doesn't work. Did I screw up something when I went through the MCV assembly??? I pulled all of the valves and put new springs on them. I believe the red light comes on when the TA is pushed forward and is off when the TA is pulled back. I hate to split the tractor and put a TA in it if that really isn't the problem. Should I pull the MCV valve body off and check it over again or is the TA toast? Help!!!!!
 
Yea ya probable did , now as to where i ain't even going to try and guess . Installing a new spring kit is not just a matter of taking one out and stuffen in a new one . Pressure reg spring needs to be ADJUSTED shell we say . and this needs to have a pressure check done with warm fluid . You lost pressure someplace due to maybe a blowen gskt. / o/ring maybe just a simple T/A spool valve adjustment If you have no hold back then you may also have no pressure in the T/A low side clutches and that is what gives you hold back not the sprag . Ya know it is really hard to figure some of this stuff out when your not there and you have no idea what all went on or how it was done . Now i am not getting down on ya for tryen as everyone of use want to save a buck as bucks are getting harder to come by . Pressure wise on a 706-806 i like to get them st someplace between 235-245 more horse power tractors i will go up to 280290 range . Post some side pictures of the MCV showing it up close and how the T/A spool valve is setting , ya want the snap ring on the valve touching the nuts when down or handle all the way forward. The only other thing is that you have a blowen seal or warpeed oil baffle in the T/A it's self and that will require a new T/A .
 
After drinking this over a bit , ya may have used the wrong gskts and are blocking off the two ports to send oil to the clutch pac.'s MAYBE
 
Thanks Tractor Vet. I did mention that when you have the TA in the low side the red light goes out. I forgot to say this - when you are pulling the TA lever back from direct drive - about 1/2 way is when the red light goes out. So the red light goes out way before the lever is clear back. Don't know if that helps or not.
 
Pull the MCV off and check the gskt's and make sure the mounting gskt of valve body to housing all holes match up and the same with the rest of the valve body . Make sure you did not forget the o/rings . alos make sure you did not loose the sump check plug and spring down on the lower right hand side.
 

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