Rear Diff evaluation (1 Viewer)

[Scota4570]

This is a new thread that follows up on the first.

Rear Diff. 1970, Noisy, question

I have too much noise and vibration on the highway. It has for years. It is not a grinding type of thing but a harmonic and out of balance type of thing. My rear diff has about 10* of radial slop on the drive line. The U-Joints are tight. I noticed vertical and horizontal play on the...

forum.ih8mud.com

I took the cover off the reaf diff on my 1970.

Briefly I had a vibration at highway speed in the diff. Tightening the castle nut on the flange "fixed" that. There was no preload at all. It has been worked on. There was lots of red RTV.

The gears look nice to my untrained eye. There is no apparent wear, uneven wear, scoring, pitting . The original machine marks are still on the wear surfaces. Good! ???

The oil does contain glitter. I have no reference on how much to expect. The plug magnet had fine metal on it, about the volume of a dime.

I think I may have gotten lucky. Maybe the RTV fanboy never set the preload on the pinion properly or a bearing race was not seated properly and it seated when the housing got hot?

I have no maintaince records, the previous owner has passed away.

What so you think.

See attached for photos.

 

[pb4ugo]

It's called pre load for a reason. Looks like it was loose for a while. I'd tighten the nut and run it. If it whines badly, then find a donor or swap with the frt. It's a 50+ yr old 40, a previous owner may have swapped them decades ago.

 

[charliemeyer007]

I have seen way more metal than that. You need to mark up the gear and see where they run.

Amazon.com : gear marking compound

 

[B y r o n]

If you're looking for references as far as setting the gears then you may want to look through some of these builds.

 

[peesalot]

Thats not too bad, looks like someone put new gears or bearings and that is normal for a breakin oil change. Tightening the pinion nut can solve the issue you had, I would change the oil again after a couple hrs of driving and check that pinion bearing for play when you do, after 1 check up if you dont find any continued issue , run it. I have found that when the pinion nut is loose it is because the bearing has failed or worn, tightening works for awhile, could work long term but that is why I recommend checking it after some run time. When you tighten that nut and the bearing is beyond using the feel will have a ratchet or notchy feel when turning, that is time to rebuild.

 

[Scota4570]

I tightened the pinion nut "real tight" holding back with a large pipe wrench on the flange and torqueing the nut with a large socket wrench. The book calls for 160 foot pounds. I probably got close to that with a 2' breaker bar. The pinion bearings are perfectly smooth and run free.

As noted above the gears look great. I did not check that mesh. I have no way to do anything about it so I left well enough alone. I replaced the beat up plugs and made a new cover gasket. I put in new CLEAN gear oil.

It runs good. There is no noise or vibration coming from the diff. IT is a huge transformation. It is better than it has been for years. I will drive now.

Next task, get the slop out of the front end. The steering box is relatively new.

Thanks for the help.
Scot

 

[pb4ugo]

There's no way to tell the condition of the bearing unless you actually looked at it. The nut might have loosen or the bearing may be worn. Time will tell. I hope it's all OK.

Imo, looking at the ring gear you can tell that pinion was riding all over place on the ring gear teeth. That's why it's all shiney. The top of the teeth show score marks too, torwards the heel of the teeth. I believe the 3rd has some miles on it. You can see witness or shadow marks from where the r&p has been meshing together for a long time. That pattern looks good. It's probably fine.
You might consider getting another 3rd, maybe rebuild with new bearings and gears for an eventual swap.

 

[sogncab]

Any marks on the carrier caps? Usually you want something to identify which side they came off of. I used a punch and a hammer so it doesn't wipe off.