John Deere 850 problem

John Maurx · Dec 18, 2011

I have a John Deere 850 that will not drive in high gear. I can use low gear and it drive in 1st only. Have lots of power but will not move when in high. Any information would be greatly appreciated. I am thinking clutch. Thanks.
John

beenthere · Dec 18, 2011

:welcome:

Need more description of what the 850 is doing, or not doing, and what you are doing that leads to it not moving.
i.e. why do you think it is the clutch?
What led up to this? all of a sudden, or slowly been getting worse?

John Maurx · Dec 19, 2011

Thanks for the reply. On this tractor I have a low speed ( 1st to 4 gear) which is normally used to pull a load at slower speeds. It also has a high speed ( 5th to 8th gear) for speeds up to 13 mph.
When I need to start off in high speed which would be 5th to 8th gear the tractor will not move. I have to go to low gear or 1st gear in order to drive the tractor. Since you cannot change gears unless you are stoped I am limited to 1st gear slowest speed only. In other words the tractor will only operate in low speed 1st gear. I though it might be the clutch because it is acting like a standard shift car or truck that has a slipping clutch. This problem has been slowly getting worse to the point that I can only drive in low speed and 1st gear. Thanks.
jm

beenthere · Dec 19, 2011

You didn't say, but I presume the engine rpm doesn't drop when trying to go in high range gears and the tractor doesn't move. Where are you located?

If the clutch is out, the tractor is in gear and not moving with the engine running, then you can bet it is likely a slipping clutch.

Have you adjusted the clutch linkage to specs? I'd expect you should have about a half inch clutch pedal travel before disengaging (or hearing/feeling contact with the throwout bearing). Adjust the linkage for some of that free travel.

Or you may have an oil leak that has allowed the clutch plates to become oiled down.

Smell or sight of smoke from burning the clutch should be evident.

John Maurx · Dec 20, 2011

Thanks again for your rerply.
There is no lost of RPM when I try to go into high range. Yes, you are correct the tractor does not move when in high gear. I have checked the linkage and it appears to be with specs about 1/2 inch. There is no smell or smoke. I agree with you that it is probably a cluch problem. I have about 1000 hours on the tractor. I assume there is no adjustment other than the linkage. I live in New Mexico. I was out on the tractor this morning trying to remove the foot or so of snow we got last night. I was able to use low speed in 1st gear to get some of it done. It's at a point now where even in low speed if there is any obstruction when backing up I have to go back and forth to go over it. I have ordered a repair manual to see how hard it is to replace the clutch. Again thanks again for your help.
jm

beenthere · Dec 20, 2011

Here is a thread that discusses the clutch replace.
http://www.tractorbynet.com/forums/parts-repairs/123284-jd-850-needs-clutch.html

Splitting the tractor is necessary, and aligning the parts when re-assembling are the key points, looks like.
It will be nice to have a tractor that goes when you want it to.

PHIL850 · Dec 26, 2011

I found a remanufactured Clutch for around $850 on Ebay. A new one from John deere will cost you an Arm, and a leg and another leg or close to $2000. The clutch is a 2 stage or actualy 2 clutchs in one, Drive line and PTO. You can just replace disks however, with the tractor split in two, I would do it all. The labor involved is extensive. If you do it or hire it out, replace the Throw out bearing and pilot bearing as well. If your not familiar with such a task, I highly recommend that your farm it out.

Phil C.