706 TA issues

Hello this is my first time posting to this site. Anyway I have a 706D with TA problems. First the TA pulls great in low but it will slip in high. it will eventually go into high as long as there is no load behind it or it isn't going uphill. The steering and breaks work fine. Is this an adjustment problem or is the high side out on the TA? Thanks for any help.

There are three clutches in the TA. One is a one way (sprague) clutch it hold in the Low TA position and all driving reaction torque is put on it. (it is working)
The second is the TA freewheel (lockup) clutch it is a multi disk hydraulic clutch that allows the tractor to have the ability to slow down while in Low TA when the throttle is reduced, and or going down a hill. (it is not to be used to slow the tractor by pulling it into Low TA while in road gear, or going down hill)
It is working I think) as you didn't mention an issue with freewheeling.
The third is the Hydraulic (direct drive) clutch.
It is also a multi-disk hydraulic clutch.
It is what is slipping. It is engaged to prevent the TA from having gear reduction. It makes the TA into a "drive shaft" with direct connection the the other transmissions. If it is weak (or getting reduced hydraulic pressure) it will slip.
When it slips it will not pull and reverts to the Sprague clutch in Low TA which makes it (effectively) in Low TA, slipping theis clutch until it has gained enough speed to partially lock up. (until loaded, when it slips again)
It will require an analysis of the control system, including MCV pressure, and probably a split to rebuild the three clutches, or put in a rebuilt unit. Kevin Meier, Who posts here, Hy Capacity, Maybe Rusty Farmall (who posts here) This sight, and CaseIH all have the parts. It will require a blue ribbon manual to be doing it yourself. JimN

Think yer main clutch has about had it.

Allan

There are a couple things to check before ya get all worked up On the left side of the center section of the tractor you will see a valve assembly and there will be a bell crank linkage on the top hooked to a rod and a valve , this is the spool valve tha tell the T/A what range it should be in . With the T/A lever in the forward position The T/A will be in the high range and the valve that the linkage shold be all the way don to the snap ring against the nut that hold the valve in the MCV valve body , IF it is not all the way down then it nust be adjusted and here you will need at least a IT manual to do this And follow the instructions to the letter . As this valve must be ALL THE WAY DOWN for high range and ALL the way UP for low . Next is the pressure on the MCV and this is best left to someone that KNOWS WHAT HE IS DOING to make the tests and readjusting of the pressures if they are off . And while he is doing that then he will know if by chance you have a blowen gskt. or o/ring and no allowing all the pressure to get to the cluch pack . Then there is the clutch free travel setting and along with that adjustment is the setting of the transmission brake and then the dump valve and all of these MUST BE SET CORRECTLY as well I have out line this many times on here for guys and my way of doing this is not hard but takes two people to do it and it is almost fool proof If you read it and understand it . It is not common for the high side to go out but it can happen . Myself i would run the tests first and look over everything before i started to spend money . Then i would take a long look at the Main clutch as it maybe weak and plum slap wore out or you may have one or both seals leaking oil onto the clutch from either the transmission input shaft or the PTO input shaft . If there is alot of leakage under the ceter section under the bell housing then this would be your problem . But i am here behind the key board and can no5t look for my self so we are all guessing . So find someone in your area that is a GOOD I H mechanic and let him tell you what is wrong .

Thanks for the replies i will adjust it tonight hopefully. And there is a fair amount of oil leaking into the clutch housing. But if that is the problem wouldn't it slip in low too?

Yes it is sure to have the slipping effect on both if it is the master clutch. If it is not an adjustment, or the lockup clutch apply oil pressure, it will probably be the lockup clutch.
If you must drive it, and it pulls in TA Low, do not use TA high. JimN