M670 super doesn't move

Rbear

New User
using my M670 to move lg rd bales on small acreage had 3 lined up flat side to flat side close to each other. The 4th the tractor hunger in reverse and couldn't bump it to neutral so tried to rock it a little by letting clutch out quickly to friction point then back it keeping pressure on shifter. WRONG THING to do. Heard a metallic snap or crack and it went to neutral but now it doesn't move in any gear. PTO works. 3 point works. Looking up in inspection plate to clutch no damage visual and all turns when running. Hoping a key snapped that connect a shaft to a gear on the way to the pinion. Anyone have an idea what I screwed up?? In north Texas looking for Mechanic that knows MM's.
 
Next time shift the amplitorc to low range to ease shifting like the sticker on the dash says. Couple things to check to narrow down the problem. There is no key to shear off. Remove the adjustment plug for the amplitorc and inspect things as good as you can through the hole. If the cage or a gear broke, you can probably see it. Next would be to pull the transmission cover off. It's only 10 or 12 bolts. With that off, you can inspect all the gears and shafts to see what does or doesn't turn. If all is turning okay and looks okay, the problem is back further. If the issue is in the differential, you will have to pull the hydraulics to get a peek. At that point, may be easier to find a back half of another 670 super.
 
Sounds like you may have broken the lower end off the shifter. It would still move the lockout portion so you would feel some resistance but would not move the shift rails.
 
Thanks Chris. Not sure about sticker but if it?s legible I missed it. It?s was always a little difficult to get out of gear
when it got warmed up. I did tow it to where it?s parked. Is the transmission cover under the shifter ?
 
Jk it did come out of reverse. I wasn?t very clear on that then towed it out of the hay shed. That?s good to know. Thanks for the reply. Haven?t taken anything apart. Been reading a shop service manual I bought on eBay about 2005 when I picked up the tractor. Should of sprung for an operators manual too I might of been aware of what Chris said about the amplitorc. I?m a bit leary about opening this up yet. Still trying to understand this beautiful old beast 🤠
 
Yes. Just take off cover and see what's not turning. Should be able to turn motor over by hand and watch shaft. Probably in torq setup.
 
Does the shifter feel normal when you try to shift in the different gears? Or does it feel loose and s little sloppy? Does it feel like you are moving the rails and shifting forks moving gears or is the resistance on the lever less than normal? If everything feels like it did before this happened, then start the tractor leave the clutch engaged and gently try to move the shift lever into a gear. You should get a good solid stripping of the gears. If not probably in the
ampli-torq. Did you try it in both high and low range? If no action in high or low you may have stripped the worn splines off the input shaft. Or hub could have broke out of the clutch plate. With two people and a careful operator on the seat. take the adjustment plug out on the right side for the ampli-torq. With a good small light and someone looking through the hole and the tractor in gear, ease the clutch out and see if the ampli-torq clutch is rotating. That should answer your question.
If you have doubts it is much much easier to take the top off the transmission that to split the tractor.
MMDEL
PS: In any event when you find the problem PLEASE let the people on here know what you found out. So many time fellow MM friends give very good advice to help some one and never hear if the problem got fixed or not.
 
mmdel thank you. All this with the other responses helps greatly in understanding this. We had a lot of rain Friday night and a bit of freezing rain/snow yesterday morning. Got a little straightened out today. Maybe tomorrow I can look inside. Hope this problem is up front.
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Thanks I will take a look. Needed some encouragement and direction. The amplitorc has always been forward so I think that?s high range and engaged. Sure appreciate all this help from all of you.
 
No wonder, If it has always been in high range that makes for a difficult operating tractor. Very hard to shift in high most of the time. As was stated before your decal must be missing.Start it up put it in low range and see if it moves. How ever the oil should be warmed up be for it is used in low range. There should be another decal telling you about that. Best get an operator s manual and read it from cover to cover. With that new information (always in high) the ampli-torq clutch maybe rotating, But the clutch plate ears may be sheared off.
MMDEL
 
WOW yet another key reply!!! I did order a operator?s manual
Saturday night from yt. You guys are great!! The 2 hinge are
part of a cover I made from aluminum for the gauges. That?s
the grey.
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Forgot to ask...... what oil has to warm up with amplitorc in high before using low??? Engine oil or hydraulic or is it just what?s in the transmission??
 
It's what's in the transmission. It doesn't have to be hot, but it needs to be flowable. If it is cold and stiff especially in the winter, the torq sprag is slow to grab the torq hub and will slip and wear. In the hot summer it isn't much of an issue. It is most problematic when shifting from High range to Low range on the fly with out clutching. Any time you feel it slipping in low range, kick in the clutch and let it out a little slow and it will usually grab and work all day. It doesn't need to be warm to shift gears. It is always easier to shift in low. Especially in the winter.
NNDEL
 
Ok thanks. My operator manual will be here any day. I live
south of Decatur Tx so we are pretty mild. These tractors 🚜
must of been a great help to farmers when having different
soils to work and all. Sometimes in the same field I would
imagine. Dang nice engineering it seems. Thanks for the
through explanation.
 
Ok today 1/14/20 Temp 62 started engine left run for 5 minutes with clutch out. Pulled amplitorc to low range and shift to forward gear & release clutch just some low metallic noise no power/movement reverse same. Shut off & remove transmission cover and start engine. When clutch depressed no metallic noise, sliding shaft & gears slow to a stop, shaft under that, I guess the clutch shaft, continues with power. Metallic noise returns when clutch is left out at friction point and sliding shaft & gears start turning again. Clutch depressed & amplitorc pulled to low and same thing repeats. Gears look good in transmission. Metallic noise seems to come from in front of trans in amplitorc sounds like teeth sheared off & smooth pipe or metal rotating on ruff edges.
 
I believe there is an inspection plate under the clutch. I know the M5s have those, I'll have to check on my M670 Super to make sure but you might want to just check in the clutch area also. You can see a lot through the adjustment plug on the side of the Ampli-torque compartment. I changed some cotter pins through that hole lol.
 
Finally received my operators manual today from yt. How does the filler plate front compartment on the rightside for the ampli torc come off??? Mine has a medal strap like a popcycle stick bolted across a plug with notch to hold plug in and keep from turning. Does the plug thread out or just pull out with a puller?? There is a 1/4 20 threaded hole in center of plug that is uncovered when metal strap is removed. I drain the front section?amplitorc? the oil was like sludge the other day. If left in forward position would it be safe to use a lighter wt oil than 80 gear lube to idle for a flush.
 
(quoted from post at 00:32:42 01/24/20) Finally received my operators manual today from yt. How does the filler plate front compartment on the rightside for the ampli torc come off??? Mine has a medal strap like a popcycle stick bolted across a plug with notch to hold plug in and keep from turning. Does the plug thread out or just pull out with a puller?? There is a 1/4 20 threaded hole in center of plug that is uncovered when metal strap is removed. I drain the front section?amplitorc? the oil was like sludge the other day. If left in forward position would it be safe to use a lighter wt oil than 80 gear lube to idle for a flush.

If I remember right, When I loosened the cover up a little, I slide it to the side enough so that the end of the bar came out through the hole with the cover.
 
UPDATE 2/17/2020 after Chris Q explained the transmission shaft was hollow for the power takeoff shaft to go through I took the top of the trans cover off after putting transmission in 3gear. Then started with clutch disengaged, pedal down, nothing turns in transmission. Letting clutch pedal out, engaging, transmission shaft still doesn?t turn and noise starts so apparently the amplitorc and or front end of transmission shaft is damaged. Differential doesn?t turn nor anything in transmission. When I get this split I will let y?all know what I find. This might be awhile till I round up the equipment. Thanks to all for your input.
 
Trying to add video of 2/17/2020 UPDATE
Don?t know what format or how to enter info. From iPhone
 

Video of transmission in 3rd gear and start up with clutch disengaged pedal down. When pedal released clutch engaged no movement in transmission noise starts must be amplitorc damage and possible front end of transmission shaft.
 

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