Rear axle clunk?

[sjg56k]

Hi, I have a 1950 8N with a Sherman combo tranny. I just bought it from a neighbor. Noticed driving home a rhythmic clunk about every 3 revolutions or so of the rear tires. Some gear I guess but the every 3 rev's. or so has me wondering which one has the bad tooth or something? Experts please. Thanks. Love that tractor though. Runs well. Will paint. Thanks for any ideas.
 

[Ultradog MN]

Check/tighten your lug nuts And the rim to
center bolts.
 

[old]

Make sure the bolts that hold the rim to the center are nice and tight
 

[sjg56k]

Yes I will check tommorrow. There are new tires and outer rims on the tractor. ( Neighbor said cost around $1400)
 

[sjg56k]

Oh also I seen the pulley behind the fan is really loose and wobbly when I wiggle it, but the water pump is not leaking any? Thoughts?
 

[Abbby]

First check if the four bolts holding the fan are tight. If they are and the slop is in the pump you should consider changing it right away. You do not want the fan coming out of the pump and taking out you radiator costing you another $300.
 

[sjg56k]

Word! Thanks
 

[Abbby]

If wheel bolts are tight jack up each side and push\pull on the top of the wheel to see if there is slop in the axle bearings. Maybe someone did not shim it correctly. Also slowly rotate the wheel to see if you can reproduce the noise.
 

[sjg56k]

Sounds like a good plan. I'll let you know. Thanks.
 

[sjg56k]

So I'm back. I checked all of the above mentioned possible issues. Lug nuts where not very tight. Big axle nuts where just a little off there torque., outer rim nuts where tight. No Joy. Rhythmic clunk persits. About every 3 rear wheel rotations I hear it pretty obvious. Sooooo- Bull gear maybe?? Can I check this through a hole somewhere?? Thanks for thoughts.
 

[sjg56k]

Oh I forgot. Also no real side to side play at axles either. Just a tad.
 

[sjg56k]

As noted below I think I checked all the possible problems but no joy. The every 3 revolutions or so for each clunk has me stumped. Could it be a tranny gear or something. Does the big bull gear turn once per tire revolution?
 

[deanostoybox]

The differential ring gear turns once per tire revolution.
From on old post in the archives https://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=nboard&th=610343

ALL N-Tractors have the same diffy gears (6.66:1) ratio.

So I guess if there were to be a damaged tooth on the ring gear and also a damaged tooth on the pinion it could be possible that the damaged teeth just happen to come together every 3 1/3 revolutions of the rear tires. Maybe. IF that is your problem.

If you pull the left axle trumpet the differential assembly will come right out. It is heavy. Then you can inspect the gears. Maybe if you pull the PTO shaft and have one rear tire off the ground and a helper turn the tire while you watch through the PTO hole you can see if there is any damage to the ring gear. Or stick an inspection camera in there you can see better.

Sometimes the bolts or rivets that hold the ring gear to the differential come loose. One would think in that case the noise would be happening more often. Same with something amiss in the transmission.

I don't have any ideas, sorry.
 

[sjg56k]

I like that train of thought. I will pull the pto shaft and tale a peak. Thanks
 

[sjg56k]

I have cherry picker. Can I pull the left axle trumpet less tire as a unit with the axle still in it?