[dataway]

I've got a midsize 6 ton press, quite a bit of tooling, and I can always make any necessary tooling on the lathe. I think I'll give the splitter type a try since I have the press if needed and I can certainly use it for other applications.

I have a selection of two and three jaw pullers already also.

I'm saving all these links, most of those didn't show up in my searches.

I'm feeling a lot better now that I'm not going to get this thing apart and then not be able to get it back together again. I'm not considering what I'm doing now a permanent fix ... I could be moving my whole shop to TN at some point in the not too distant future, I need to keep the GTO mobile under it's own power, but not necessarily in condition for a road trip. Once in TN I'll have more resources to apply to a more permanent or higher quality solution.

Very much appreciating the help I'm receiving here.

[dataway]

Here are some photos of the carrier bearings etc.

The outer races are smooth as glass, both carrier bearings under hand load are smooth as silk and completely silent. You could tell me they were new and I'd believe you.

Ring gear and pinion look fine to me ... but I'm just saying they have no visible damage, scoring, weird looking wear etc. I don't have an educated opinion when it comes to these gears.

Checked the new outer axle bearings, both perfect.

Even checked the rear universal (new), feels great.

Only issue I see with the diff is the spider gears .. they will move axially along the cross shaft probably 20-30 thousandths. As if their shims are worn.

When I spin the pinion ... it makes noise, feels smooth, no end play, no axial play ... but after feeling how smooth the carrier bearings feel I wouldn't expect the pinion to make that much noise. Kinda of a smooth consistent rumble. Depths of the pumpkin were perfectly clear of any metal, or any glittering. I'll remove the pinion next and take a look at that. The pinion nut came off with what felt like normal effort using a tool to hold the yoke. The pinion spins absolutely freely, so a torque wrench on it would read absolutely zero.

[mrennie]

A few thoughts:

-no obvious visual issue in your pics

-I am not surprised the spider gears have some play along the shaft. IMO manufacturing tolerances make some play a requirement or they would be hard to install, and I believe that under load they are pushed against the carrier and side gears due to the angle of the teeth. I don't think this is your noise problem anyway since as you pointed out, they do not rotate when you are driving straight.

-pinion should have some preload even if worn. Going completely by memory (subject to correction) but I believe used bearing should require 10-15 in lbs to rotate compared to 20-25 for new bearings. With the pinion bearing preloaded I think it would make some noise but your description sounds like more than a little. Will be interested to see what they look like when apart.

[dataway]

Yep, the pinion has zero resistance to turning, you can pretty much "spin" it.

So question to you guys is ... replace all the bearings while I have it apart?

And yes, the spider gears move against their shims with the slightest meshing pressure on an adjacent gear.

[dataway]

I don't claim to be a roller bearing expert ... but this doesn't look too good.

The inside pinion bearing and race. About 30% of the rollers look like that, varying levels of damage to the others from almost none, to just as bad.

Picture of the race showing the two bad spots that probably lead to the destruction of the rollers.

Front pinion bearing looks fine, pinion gear looks acceptable to me.

Lesson learned here ... oiling and fitting that bearing by hand into the race ... it feels smooth as can be, so you never know.

Still ... I'm not sure if this was the problem, again I have to stress that the pinion had zero slop in it that I could find. However, if lack of preload can cause a whine like that .. well maybe this was the problem, cause the pinion didn't have any ... probably because this bearing "self clearanced" itself

So ... all new bearings you think? Anyone think that maybe rust could have caused that damage? Sitting around outside for probably 30 years. (saw no other signs of rust inside the pumpkin)

PS. Why didn't you guys tell me how hard it is to remove the yoke Required a 2 jaw puller and a decent size impact gun.

[PunchT37]

There`s your noise.

[68 Firebird]

That’s exactly the same pitting mine had on bearings and race.
Only in the top side, where no oil was.
Gerry

[Greg Reid]

I never feel like I wasted time changing obviously bad parts even if it doesn't fix the problem I was chasing.

[Shiny]

Glad you found something that might explain the whine.

That is clearly an unhealthy bearing, so replacement is a no-brainer whether it's the source of noise or not.

You haven't shared any other suspect wear patterns but given the condition of this one and the work involved to get into it, I'd be replacing every bearing in there.

Hopefully you measured the pinion depth. If not, do it before removing the bearing. Replacement bearings may be identical but you know you're always safer to verify and you have the tools and ability to do it.

Why it failed? I doubt it was overloaded nor run beyond its design life, but they are made of hard and super-strong materials like 52100 or 440C to mitigate risk for contact fatigue failure and resist wear by suspended hard particles. IMO, a mature and robust design like this would have almost no risk for fatigue failure unless something weird happened to overload it. Perhaps loss of pre-load contributed but not sure why.

Bounce those images off an experienced supplier/rebuilder and they might recognize the cause and help you gain confidence in the noise hypothesis.

Great photos BTW!

Speaking of, the sharp lines on the gear faces look unexpected to me if they are a wear pattern. You've probably seen a zillion images of "ideal" contact patterns and I doubt any of them had sharp lines near the edge of the gear face.

Again, I'd bounce this image off an experienced rebuilder and see if it's consistent with loss of pinion bearing pre-load or some other alignment concern.

[Held for Ransom]

I think the rust formation on, wasting of, the bearing had been there for a while. I think you being able to hear it was because of the change to the thinner gear oil.

[NeighborsComplaint]

Yup.

Pinion bearing just like I said. I've heard it many times. Had a Ford 9" just like that. When you accelerate, the pinion tries to climb up the ring gear and wears the pinion bearing. When you decelerate, it tries to walk back down but is loaded much less. Drive on it too long and it cups the face of the ring gear teeth and makes a knife edge.

[dataway]

Yes I took that picture of the pinion gear specially to show those very defined contact marks. There is no edge or lip there, perfectly smooth. I'm not sure if they are pressure contact marks, or due to some other cause.

The gear has what I would call well defined edges, but not the razor sharp edges you would get from excessive wear.

Bearing is still on the pinion .... question is, would I get an accurate measurement of pinion depth with this damaged/worn bearing? In this situation I want the pinion depth what it "should be" rather than necessarily "what it is". The gear set spent I'm sure the vast majority of its life span with the OEM clearances BEFORE this bearing failure ... so I'd like to return it to its "born with" relationship, rather than the relationship it has now with the worn bearing ... or at least that's my thinking.

At present, for better or worse, the gear set will remain, as a new 2.93 gear sets don't appear to be made anymore.

So the plan is ... replace all bearings, use original factory shims ... see what the result is when it's all back together.

Going to use all Timken bearings ... so hopefully their current sets of the same bearings are within a couple thousandths of the originals ... my experience with their other bearings is that this wouldn't be a concern. I think the smallest shim size interval is .002" so ... within that tolerance I should be OK.

I will set the pinion and bearing up on a surface plate and measure from the outside of the bearing race to the end of the pinion gear and then compare it to the finished product with the new bearing before installing it. Off the top of my head I'd expect it to be .001-.004 deeper due to wear on the old bearing and race.

Yes it's somewhat of a pain in the butt this whole job, but not bad. If it turns out the bearings don't quiet things down it's not a huge deal to pull it apart and try another solution.... which would probably end up being a new carrier and new gear set.

I'll keep everyone posted on the outcome, going to order a bearing splitter and the bearings tonight.

[b-man]

I’d be so tempted to put in a new set of 3.08s and an Eaton posi.

Why not upgrade to posi and a little more gear now that you’re this far into it.

The 3.08s are a highway friendly gear that’s pretty close to the 2.93s you have now.

[dataway]

Believe it or not, I basically have no interest in performance mods, not on vintage cars anyway. To me a posi is just another thing to go wrong. But, at some point I may have no choice but to go to more available parts.

Now that I've dug into this kind of thing it strikes me as just a weekend project to do just about anything to a differential, WAY less work than a trans or engine coming out.

I've got an Eaton locker in my GMC truck ... is that the sort of thing that can be swapped into a 8.2 rear end these days?

What am I limited to as far as carrier type with an 10 bolt rear? I know I can go up to a 3.23 in 8.2 ... I assume an 8.5 rear end is a totally different axle/diff?

See what you did ... just spent a few minutes looking at the Eaton posi, what a nice piece of work. I'd think if things don't work out, I'll be doing just what you suggest, both the Eaton posi unit and 3.08 gears sounds like a good idea. Just wanna try this $200 fix first. Eaton would probably have to wait till I make the move down south though.

[dataway]

Since I had already driven the pinion bearing races out of the case this is the dubious setup I plan to use to compare pinion depth after the new bearings are installed. I placed a mark on the top of the pinion gear so it gets measured in the same place ... as it's no where near flat.

I'm also thinking if I mic the old bearing thickness with race installed and compare it to the new bearing thickness that should pretty much tell the whole tale. Assuming the new races are seated properly, and the old shims are used ... only wild card is the space taken up by the bearing and race .... which ideally should be the same as the OEM original bearing, and I'm guessing Timken is pretty good about that.

[Shiny]

You clearly understand all this and your thinking about returning to the original setup makes sense to me.

My valueless guess is replacing the bearings and re-assembling will fix your whine.

Hopefully your new bearings will match the dimensions of the originals. A set of calipers should answer this.

If not, and you need to start shimming, I'm not following your pinion depth measurement. Are you planning on leaving your dial indicator setup alone and pull the pinion in and out of it? I don't see how else you are measuring anything you can repeat but I'm probably missing something.

The new gear set I bought had pinion depth stamped on the pinion. It represented the distance between the pinion gear face and the CL of the ring gear. The depth was the setup used in the factory to burnish the gear set. Apparently they run them in with an abrasive (ie lapping and/or polishing) after machining and the goal is to match their setup in your axle.

Not having a special tool for finding the CL, I used the ground faces of the ring bearing saddles as the CL (caps removed). I bought a precision-ground bar, set it across the saddles, and measured to the pinion face. Adding the bar thickness gave me the installed depth.

In your case, I agree it is not worth the trouble if the bearing dimensions are identical to originals. All you need to do is replace them and you should be good to go.

Mike

[dataway]

Well you've perfectly pointed out why my setup is "dubious"

The setup there would measure from the rear face of the pinion gear to the front surface of the rear pinion bearing race. Which would do nothing but give a comparative measurement of the "stack" ( stack of bearing, shim and pinion gear). It would give no actual depth reading, would just compare old setup to new setup stack height.

I'll check my OEM pinion ... but the rear face at least is no where near flat, so it would be very hard to use that for a reference of any sort in a setup in the diff case.

But since all things are equal except the unknown of my new bearing thickness ... that should kind of be the "go no go" if additional shimming will be required ... then a whole new ball game starts.

What are the odds my indicator will not be jostled around putting in the pinion with new bearing ... probably about 20%

[Shiny]

Originally Posted by dataway

Well you've perfectly pointed out why my setup is "dubious"

Definitely not my intent! You have a surface plate and know how to use it, which greatly exceeds my token metrology!

The setup there would measure from the rear face of the pinion gear to the front surface of the rear pinion bearing race. Which would do nothing but give a comparative measurement of the "stack" ( stack of bearing, shim and pinion gear). It would give no actual depth reading, would just compare old setup to new setup stack height.

I'll check my OEM pinion ... but the rear face at least is no where near flat, so it would be very hard to use that for a reference of any sort in a setup in the diff case.

But since all things are equal except the unknown of my new bearing thickness ... that should kind of be the "go no go" if additional shimming will be required ... then a whole new ball game starts.

I agree. If the bearing dimensions match, you are unlikely to need to measure anything, but if not, your setup can at least guide you on more decisions.

What are the odds my indicator will not be jostled around putting in the pinion with new bearing ... probably about 20%

I am more optimistic than you. Now that you've put it out on the web, you will be motivated to maintain your dignity and reputation so I give you a 96% probability of succeeding.

But all BS aside, I hope you can find a set of bearings that are good quality.

I don't think this application is too demanding as far as bearings go, so any name brand should be high confidence. I haven't worked with any suppliers for 6 or 7 years and we all know the world of parts and manufacturing hasn't improved lately. I would have trusted Timken, SKF, NSK in the past but who knows today? Kind of like the recent fuel pump thread, brands we used to trust keep selling off, changing names, changing specs, and in general, avoiding responsibility. Not an issue when cost is the only criteria but good luck finding out about the reliability of anything sold today.

A few calls to the rear axle part suppliers on your list should get you some good advice.

Mike

[PunchT37]

Get 2 new Timken pinion bearings, use your original shim, set bearing preload for new bearings with new crush sleeve. Then, get 2 new Timken carrier bearings, use the origional cast spacers or shims. Fill with good GL5 80W90 oil. Run with tires on, on jack stands, for 20 minutes or so, idling in high gear. Then, hit the road.

[dataway]

All new Timken bearings are on the way, new sleeve, nut and complete shim set just in case.

Since I've got it all apart ... should I test the preload with just the pinion installed? I see the service manual calls out a process where the entire rear end is assembled brake drums and all when setting pinion preload.

Shiny ... I think the "dignity" ship sailed a long time ago and I wasn't on it

BTW last night I cut off the carrier bearings, used the Dremel method instead of puller, worked very well. Didn't even bother trying my jaw pullers, but the carrier does have notches for a two jaw puller, I do think they would have pulled off easy enough ... in case anyone is trying to decide whether to buy something "fancy" to pull them off.

No surprises, the carrier bearing inner races looked fine. On close examination the front pinion bearing also had pitting on the races, no where close to the what the rear pinion bearing had, but still visible under magnification. I would have posted pics but my digital microscope seems to have crapped out.