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2012-05-30 Broken 4WD


Is this a bad thing? Front wheel drive, left hand side, John Deere 870. The entire weight of the tractor, bucket, etc is carried on this needle bearing. 

Hey, where did the cage go?

One of the rollers fell into this gear, a 300 USD part.

It's a unique arrangement. From the pumpkin, it drives the 300 dollar gear shown above, then to bevel gears on a vertical shaft, then a final 90 and out. This part is also the steering spindle, so there is turning, rotation, and torque. 

It's wink link, I've broken this setup 3 or 4 times now.

Failed needle bearing cage.

Click on pix for full size image..

Pix of dissasembly John Deere 870 MFWD front left. Topside here.

Notice broken needle bearing race on left hand side of picture. Lots of force going here..

Left to Right dissasembly based upon pix above. The right most piece is a spacer, center a clip.


Ran some blueing on the teeth to see how they looked. The only problem is I don't know what I'm looking at. Is this a good pattern?


Finally, Johnnie Deere is whole again. Use a dial indicator and mag base, measured slack at .0065, the spec is .004 to .006 I said close enough. Did not measure the axle driven bevel gears - same gear set, same shims, should be ok. Also ran a dye check again and it all looked good for the output gear set (the big one) that's supposed to be .004 to .006 and it looked close enough.

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