JD 850 Grinds Gears after 10 mins in Hi gear

[cmoo]

It's a JD 850 2 wheel drive!
I had mowed (bush hogged) a pasture for an hour, depressed the clutch, put PTO in Off and tractor in 8th (Hi) gear then drove down the pavement for ten minutes to the next field. Never been in Hi gear on pavement and thought the tractor went really fast. As I decelerated turning off the pavement the temp light came on so I drove straight to the spicket 150' away. Raised hood ran water over the radiator (95 degrees that day) and the light went out very soon. Got back on the tractor and could not get it in gear (grinding as if no clutch), but the PTO would shift into gear when I depressed the clutch.
Let her set overnite and problem still there. Remembered the "Freeing up rusted/stuck clutch" trick of pulling up to a tree, but the back wheels just dig down. Had the tractor for about a year (made 78-88) so clutch may have just went out, but it never even slipped before this. Could be tranny? Any ideas would be welcomed? It's a two stage clutch. Had to crank it in gear to get it back home.




Starting to lean toward tranny problem. Changed Hydraulic oil, cleaned filtering screen and adjusted clutch that didn't need adjusting with less pedal play. Cranked tractor:
1) Depress clutch and engaged PTO, ok.
2) With range shifter in neutral Tranny shifts into gear, but range shifter won't (grinds). Next, put tranny in neutral and range shifter goes into High and Low range, but tranny won't shift into gear (grinds). Puzziling!

 

[jeff9366]

I mowed (bush hogged) a pasture for an hour, depressed the clutch, put PTO in Off and tractor in 8th (Hi) gear then drove down the pavement for ten minutes to the next field. Never been in Hi gear on pavement and thought the tractor went really fast.

In 4-WD the front wheels turn 5% (+/-) further than the rear wheels. This is to aid steering first, traction second. This is called "slip". On dirt slip causes no problem.

On roads that 5% greater travel means the small the front wheels are are really spinning. High speed rotation of front wheels puts great strain on the front wheel drive components, axle and front tires. On roads 5% greater front wheel rotation accounted for your greater speed.

4-WD is for soft surfaces only. 2-WD is for roading.

 

[cmoo]

In 4-WD the front wheels turn 5% (+/-) further than the rear wheels. This is to aid steering first, traction second. This is called "slip". On dirt slip causes no problem.

On roads that 5% greater travel means the small the front wheels are are really spinning. High speed rotation of front wheels puts great strain on the front wheel drive components, axle and front tires. On roads 5% greater front wheel rotation accounted for your greater speed.

4-WD is for soft surfaces only. 2-WD is for roading.

I should have mentioned that my tractor is a 2 wheel drive.

 

[crashz]

Sounds like the clutch to me. Sounds like the first stage (PTO) is working, but not the second. You mentioned that the pedal play is fine, but is that only for the first stage? I could never "feel" the difference between engaging the first and second stage on my 770 and that is why I rarely use it as a 2 stage clutch. I usually engage or fully disengage.