Farmall 706

[ddean]

So just got a Farmall 706. Had the tractor split because of a stuck clutch. Got it delivered and while I was messin around, I noticed the rear hydraulic levers were stuck. Messed around with them some more and got them freed. I believe this is where I messed up. I started tractor, moved it around a bit, tried the TA and now it doesn't work. Did i plug the system from messin around with rear hydraulic levers? If so, how do I go about cleaning the junk out of the hydraulic system to get the TA working again? Any help is appreciated.

 

[Janicholson]

Welcome to YT Forums and Parts ASAP. Tough to get a clear answer for that TA failure. We need to know what "doesn't work" means. Move the lever rearward and the tractor stops, move the lever forward and it stays in reduction, move the lever rearward and it continues in direct? Each symptom describes a different issue or potential issue. Messing with stuck hydraulics (probably because they were not being used for years or decades, can put particles and decayed rubber stuff in the hydraulics, possibly getting into the MCV control structure. Does the steering work? do the brakes work? does the engine sound change if the (now working) levers are moved? Jim

 

[ddean]

Welcome to YT Forums and Parts ASAP. Tough to get a clear answer for that TA failure. We need to know what "doesn't work" means. Move the lever rearward and the tractor stops, move the lever forward and it stays in reduction, move the lever rearward and it continues in direct? Each symptom describes a different issue or potential issue. Messing with stuck hydraulics (probably because they were not being used for years or decades, can put particles and decayed rubber stuff in the hydraulics, possibly getting into the MCV control structure. Does the steering work? do the brakes work? does the engine sound change if the (now working) levers are moved? Jim

I have good brakes and good steering. When TA is in back position and throw it forward, it does nothing. Before you could feel speed pickup, now it doesn't do nothing. Yes you can here the engine rpms fluctuate some when levers are moved. So back to the TA, i believe it happened after I messed with rear hydraulics levers. I think gunk broke loose and got into the mcv and hydraulic system possibly not allowing TA to work.

 

[used red MN]

Did you try the TA before under load? Not sure how familiar you are with TA tractors and all their nuances. Applying the brakes while shifting will tell you if it is engaging solidly and if the TA high clutch is holding properly. My point is it may have been on the verge of going out and would speed up the tractor just traveling under no load and unfortunately now it has gave up. Maybe the repair shop gave it a try out doing the same thing to test the clutch and that took up some of the final hold it had left. I really don’t think that messing with the three point controls would stir up anything that would cause the TA problems, but not going to say it is impossible.

 

[tomturkey]

Had a good friend who switched from red to green because of TA problems with that era of tractors. Thats all I know about TA's. gobble

 

[ddean]

Did you try the TA before under load? Not sure how familiar you are with TA tractors and all their nuances. Applying the brakes while shifting will tell you if it is engaging solidly and if the TA high clutch is holding properly. My point is it may have been on the verge of going out and would speed up the tractor just traveling under no load and unfortunately now it has gave up. Maybe the repair shop gave it a try out doing the same thing to test the clutch and that took up some of the final hold it had left. I really don’t think that messing with the three point controls would stir up anything that would cause the TA problems, but not going to say it is impossible.

Not a 3 point, i don't have 2 or 3 point, just auxiliary hydraulics and a draw bar. No I didnt try brakes with TA. I did shift back and forth several times and it didn't seem to have an issue, up and down small hills. It seemed smooth to me. I'm assuming hydraulics all run together? I know there is a pump for mcv and a pump in rearend to run all the rear hydraulics. Correct? If so, I have lines coming from under seat, runs under floor pan, under the dash to where ever. I haven't followed them yet. I'm assuming into the block for steering? Is there anything in there they could've messed up when they split it?

 

[BarnyardEngineering]

If some things were stuck it stands to reason other things may also be stuck, such as the dump valve on the MCV. It's a little plunger that comes out the back of the MCV when you push the clutch. What it does, is release all the pressure in the TA so the driveline isn't bound up, and you can shift.

Go down on the clutch pedal side of the tractor and follow the linkage. There will be a small rod that runs back and pulls on a lever, which then moves the plunger in and out. If you can see any shiny shaft there, your dump valve is stuck and the tractor is pulling itself around on the low TA sprag.

 

[caterpillar guy]

First the rear is powered by the pump on the left side back of the left step. There is a pentagon looking cover that has the remotes pump bolted to the back of it and runs the 3 pt and rear remotes. Then there is a second pump behind the MCV to run the steering, brakes, transmission lubrication, oil cooler, and TA shifts. The IPTO has it's own pump. Now the oil goes through the same filter for the 2 pumps and then splits to go to them from the filter. Thus making me doubt the one has anything to do with the other. Now if you had an o-ring go to leaking on the MCV or at the tubes going to the TA from the MCV I could see that having an effect on the TA or even the TA was on it's last legs and finish off recently. I have found there are 2 kinds of TA's those that are about out and those that are out. Part of the reason we just delete them when we have to get deep into a tractor.

 

[ddean]

First the rear is powered by the pump on the left side back of the left step. There is a pentagon looking cover that has the remotes pump bolted to the back of it and runs the 3 pt and rear remotes. Then there is a second pump behind the MCV to run the steering, brakes, transmission lubrication, oil cooler, and TA shifts. The IPTO has it's own pump. Now the oil goes through the same filter for the 2 pumps and then splits to go to them from the filter. Thus making me doubt the one has anything to do with the other. Now if you had an o-ring go to leaking on the MCV or at the tubes going to the TA from the MCV I could see that having an effect on the TA or even the TA was on it's last legs and finish off recently. I have found there are 2 kinds of TA's those that are about out and those that are out. Part of the reason we just delete them when we have to get deep into a tractor.

So if they split the tractor to free the clutch, is there anything they may have done? I'm not pointing a finger, im just trying to figure out where to start and possible causes. The orings i can handle, i don't know about the tubes location. And more insight on this.

 

[Mrfred54]

Things to check-- fluid level, filter, TA pressures, should be around 280 psi hi and low. TA selector spool moving up and down correct distance, dump valve spool as mentioned above. Splitting the tractor shouldn't have anything to do with the TA unless it was forcefully reassembled with the splines not lined up on the input shaft, but that usually will warp the clutch plate. If you just bought the tractor, that is probably why it was for sale, p.o.didn't want to deal with it, knew it was getting bad. Good luck