806 clutch

On my 806 when it gets really cold the old girl won't move until it's warmed up. Does this have to do with hydraulics in the clutch or the TA or something else. Sometimes just changing the hydraulic filter gets me through another year.

Thanks a lot,

Appreciate it as always, Bob

In getting more information on this thing, apparently nothing in the clutch is hydraulic except for a hydraulic assist for disengaging the clutch. That seems to be an addon. The rest of the power transfer is from the TA back towards the pump/filter/oil sump. Valves, "O", and gaskets would be included.

Guessing from a laymans IQ this problem must happen even before the filter for the Hy-Tran. Possibly too much moisture in the hydraulic oil.

The tractor should move no matter what the hydraulic pressure is. It might not steer, or have brakes. The TA is a mechanical device with hydraulic controls. If no hydraulic (MCV) pressure is being directed to the TA, the mechanical TA sprag clutch will still allow movement (but at TA reduction speeds). It would not have Direct (TA forward) speeds. The fact that it is not moving at all indicates there is a failed sprag clutch on the rear of the TA. There is a hydraulic multi disk clutch that duplicates the locking of the sprag clutch but is not intended to hold engine power, it is to prevent free wheeling down hills. If it is finally getting MCV pressure, the tractor would move, and The dirsct clutch (also MCV pressure actuated) could lockup in direct TA and allow tractor normal forward movement in Direct (TA lever forward), but it would slip and fail to pull when the lever was pulled back. I think there are two issues. The sprag clutch (one way clutch) is faulty, and the MCV system is getting air in it, or MCV pressure is low. The following will not fix the sprag clutch but might make it move in direct drive. Put 5 extra gallons of Hytran fluid in the filler. (over the full mark) It hurts nothing and masks a suction problem with the MCV pump. I would not operate it in TA reduction (lever back) untill fixed. Jim

Thanks Jim:

It's been pretty consistent with the cold temperature thing. None of the hydraulics work until it's warmed up - no brakes, steering, or hitch. Plus it doesn't move regardless of TA position. Once warmed up in the winter, everything works fine and in warm weather there's no problem. The TA works on both sides in warm weather.

Oddly, when I bought the tractor years ago the TA didn't work on the low side,but I really didn't need it for what I was doing. One night I happened to move the TA to the low side by mistake and left it there over nite. The next morning I started discing and everything moved slow and I noticed the TA lever on the low side. It's worked well ever since, both sides, even with a deep subsoiler I put together.

I'll try the over fill you suggested. Have a great Thanksgiving Day!!

Well you probably have milky looking Hdy oil.and the hyd. filter is doing it's job of tryen to strain out the moisture . If the fluid is milky the bypass screen will get plugged with ice cristles also and not allow the MCV pump to pick up prime ,then like jim said the low side of the T/A is out to lunch . And of the newer tractors with the Hyd . T/A will get heavy condensation in the transmissions and rear ends and once that water gets mixed in with the oil and the lack of regular filter changes then you have problems and the more this happens the more the MCV pump is run dry and that leads to a trashed out pump . Tractors that set around and only used for short periods give the most problems with condensation . The filters should be changed alot more often .

Thanks Tractor Vet:

This tractor is a snow plower in the winter and light tillage and hay the rest of the time. Yes the hyd oil is milky. The filter is changed about every year, but the oil isn't even close to that.

So the MCV pump plugging up with ice crystals is central to this thing. That knocks the prime out of that pump and the prime isn't back until the crystals melt off with the warming up?

That explains the problem then. Thanks to you and Jim for all the help. I'll do a little work on this thing, changing the hyd oil and filter. Jim suggested an over fill on the oil, too.

Appreciate the help and have a "Great Holidays" to the both of you.


Bob

Do not be surprised if this problem still hang in there even after you do change the oil and filter because you will NOT get all the water out of the system on the first try . So heres what ya do , STOCK UP ON FILTERS and filter housing gskts. , next BEFORE you start the tractor crawl under it and crack all the drain plus just so they drip and let any water ya find drip out then close the plugs , next when you have the fliter cover off make sure all the bolt holes on the cover are FLAT and not bulging . Never over tighten the cove bolts as this warp the cove , it may not show signs of dripping but it can still suck air . Change the filter a lot more often after you change the HYD . oil like after every use for maybe five filter changes till ya see nice clean oil with no milkyness maybe more . In the perfect world it would be great to keep your SNOW tractor inside where it is WARM as this way it would help on condensation build up . That tractor will make a lot of water from being warmed up the stuffed on a cold building and as it cools down moisture build and what build inside runs DOWN into the sump then ya fire iot back up and that moisture gets sucked thru the pumps and mixed well with the oil and then the filet trys it's best to strain it out and the water freezes in the form of ice Christel and plugs the filter now the bypass is sucked open and the ice Christel now plug the screen . Now if there is enough moisture in the HYD oil i have seen them plum Freeze solid in the rear ends and NOW you have one froze up tractor and they will not even run because the constant mess gears that turn in the transmission are froze solid . One neighbor next to the old shop had that happen to his 766 one really cold winter when it dropped down to 20 below . I had five tractors setting there for sale and two of my own only tractor setting outside that would start was my old S/H and my S/MTA only because it was inside the shop . He needed to grind feed and we put the S/MTA on his grinder . we tried everything to get his 766 thawed out , He had it in a three sided pole building and we put two 150000 BTU space heaters on it put a tarp over it and after two days non stop cooking this 766 we gave up . That tractor never thawed out till mid April and when we drained it we got like six gallon of water before we got oil.

6 gallon of water. Good grief. My 806 has sit for a couple weeks. I've been using my 350 for the odd stuff. I think mine has 3 drains under the rear housing so I'll drain the water out of those. It's supposed to be warmer here in Iowa the next couple days.

Appreciate the information and hope ur Holiday went well.

Bob