Clutch or TA slipping

I got a 856 this summer and I tried it out for the first time with a disk. The first day it work fine then the next day when I was disking I stop then tried to take off and the tractor just stood there until I pulled the TA back then it took off, is this a TA, clutch or MCV problem? If this is a TA or MCV about how much are we talking about to having it fix by someone? I check the oil and it was a little low so I add about 2 gal. So I guess I need to change the filter next but the guy said he change the filters before I bought it but who knows what he really did.

There is a mechanical sprag clutch in the TA that, if in good condition, will pull even with no hydraulic pressure.

The fact that your tractor would not move at all means that this sprag has failed, so regardless of what else is or isn't wrong, your TA is shot and needs replacement.

Figure $5000-$6000 to pay a mechanic to do it. There is a service that will fix your TA section if you take it out of the tractor and ship it to them for around $2000, but that's only if you do all the rest of the work yourself and doesn't include the other things you should replace while you're in there like the MCV, clutch, and IPTO drive gear.

(quoted from post at 18:02:37 11/30/17) I got a 856 this summer and I tried it out for the first time with a disk. The first day it work fine then the next day when I was disking I stop then tried to take off and the tractor just stood there until I pulled the TA back then it took off, is this a TA, clutch or MCV problem? If this is a TA or MCV about how much are we talking about to having it fix by someone? I check the oil and it was a little low so I add about 2 gal. So I guess I need to change the filter next but the guy said he change the filters before I bought it but who knows what he really did.

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Will it hurt the tractor if you run it with the TA pull back. and when you say replace it do you mean fixing the old TA or put in a new one.

When the Spragues are out doesn’t it stop when the TA is pulled back? At least that’s what it did to me several times on the 1086.

(quoted from post at 20:11:10 11/30/17) When the Spragues are out doesn’t it stop when the TA is pulled back? At least that’s what it did to me several times on the 1086.

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No the TA seams to be working fine when I'm not disking.

If I understand it pulls fine with TA back.
That would mean sprag good but high side
clutch disks out due to wear or low mcv
regulsted pressure. Still means split time
now. Could just run low ta if you can stand
it.

No, the sprague should still pull if the high side is out, it will just seem like the tractor is "stuck in low TA."

If it stops completely, the sprague is no good.

When you pull the TA and it starts moving again, it is driving on the "anti-freewheeling clutches" which are not meant to pull a load, only to hold it back when going down a hill. Those clutches will not last long pulling a heavy load.

Disking is a heavy load. It drives fine when not disking because the there is no load on the tractor. The TA clutches hold well enough to move the tractor around, but not to pull much of anything.

Normally the TA unit is replaced as a unit. You get a rebuilt unit, and send your faulty unit in as a "core exchange." Just like buying a replacement alternator at the auto parts store.

Well with out being there to play touchy fee, and not put the gauges to it check this and check that , We are all just guessing . First off Lets check for clutch free travel and mzke sure you have 5/8th's inch free travel on the clutch pedal. Next does the red light come on when you have the clutch pedal pressed down ?? IF no red light then FIX red light , This will tell you if you have a pressure loss in the MCV circit . Next check the T/A spool valve IS it going ALL THE WAY DOWN AND IS THE SNAP RING TOUCHING THE valve nut?? . That valve MUST GO ALL THE WAY UP and ALL the way DOWN . I will tell you this that in all my years of tractor buying and selling i have NEVER and i don't care where it came from bought a tractor that was FIELD ready as there was always one thing or other that needed repaired or rebuilt . Now on yours it may be the main clutch and that is expensive enough when done correctly, and if it is the main clutch you will want to have the flywheel ground and for a 856 i always used the 6 pad clutch with the standard pressure plate , You do not want the HD pressure plate unless you have a Hyd. assist clutch pedal your left leg will thank you . when installing a new clutch you want to install a NEW IDPTO shaft AND BEARING at the same time , yes it COSTS more but it's alot better to do this then say three to five years down the road it fails and you have to split the tractor again and buy everything again . IF you have never split a tractor then either send it out or find a GOOD OLD mechanic that knows what he is doing and give him some Christmas money to HELP you .

If the master clutch is slipping the tractor will act like it wants to move, and the engine will be loaded down solidly. If the tractor pulls the disk in lower gears just fine,
the Master clutch is likely bad. If the Tractor (when it didn't move) was acting like it was in neutral, the TA sprague and the TA front clutch, or hydraulic pressure to it is at
fault. The TA, as pointed out by Barnyard Engineering, works in Low TA with no oil pressure. If the sprag clutch is going out, it can slip even then. Jim