JD 1070 MFWD problem with 4x4 staying engaged

[Rob317]

I recently bought a '90 JD 1070 mfwd with a loader and 1,000 hours on it. After using it to backdrag an area for about 45 minutes my 4x4 disengaged and I was unable to get it to go back it. The first thing I did was take off the drive shaft and immediately the ball bearings that float in the end on the front pumpkin fell out. I put it back together and after 45 minutes it happened again. I then noticed that the front axle was shifting about 1 inch back and forth. Underneath I could see that there was a gap on the frame where the pivot pin is attached to the frame. I then noticed that it was missing some shims and the bolts came loose. Does anyone know if there is something that I could look for that would make this happen or did the previous owner not tighten to the correct specs? Thanks, any help would be appreciated.

 

[Deleted member 216442]

Assuming the axle motion shifting is forward and back, that sounds like someone didn't grease the axle to frame fitting and severe wear occurred. If it is seesawing left and right, that is normal as the front axle is pivoted to follow terrain. The driveshaft is a pain with all the ball bearings to deal with. If the axle is moving forward enough it might be engaging the driveshaft but not the axle. Alternatively, the 4WD linkage is weak on these. The shift fork instead of 2 fingers is one little puck that moves the sliding gear, and forcing it in and out over many hours of use wears the puck out. When it finally breaks it will be stuck either in or out of 4WD. The fix is cheap for parts but long on labor as the tractor has to be split. After the fix, be careful to slowly move the tractor forward or backwards while applying gentle pressure to the lever to engage or disengage 4WD so as not to overstress the linkage, and little puck in particular.

I would try to shim the axle where it belongs and repair the greasing arrangement. A machinist might have to make some thick cylindrical shims for you. If you need some measurements on where the axle location should be I could measure mine for you. The pivot pin is probably ruined if I had to guess.

 

[ttroid]

I recently bought a '90 JD 1070 mfwd with a loader and 1,000 hours on it. After using it to backdrag an area for about 45 minutes my 4x4 disengaged and I was unable to get it to go back it. The first thing I did was take off the drive shaft and immediately the ball bearings that float in the end on the front pumpkin fell out. I put it back together and after 45 minutes it happened again. I then noticed that the front axle was shifting about 1 inch back and forth. Underneath I could see that there was a gap on the frame where the pivot pin is attached to the frame. I then noticed that it was missing some shims and the bolts came loose. Does anyone know if there is something that I could look for that would make this happen or did the previous owner not tighten to the correct specs? Thanks, any help would be appreciated.

I assume since this was years ago you found and fixed it?
But for the benefit of anyone else with this issue, there are 4 m12 bolts that hold the pivot pin in from the front, they have come loose and are probably gone, m12x1.75p bolts. And you need to replace the shims that also fell out when it came loose. This happened to me and destroyed my drive shaft! Chewed it up and broke the ball bearings. Cost me almost $600 in parts. Axle slides forward and disengages the balls . Not a great design.