Dana 35 pinion end play, how deep is my trouble?

I drove it 50 miles on the highway at ~70mph & then around town for a couple weeks, all apparently in this condition. Somehow it was fine. I would LOVE to know (a) how long it was like this and (b) what the long term effects would be. Don't get me wrong, I'm absolutely doing the repair. But at the same time it strikes me as odd that setting up gears requires this precise alignment but then I can be this far out and now show any real effect.

Maybe it wasn't enough miles or time, or maybe it only really creates a problem under hard acceleration? Or maybe the precision doesn't matter quite as much as legend would have us believe? Hard to say, since 99% of gears out there were set up professionally or done by people where who took great effort to get good patterns, and the remaining ones are shade tree bubbas who most likely aren't going to report that their "just send it" gear job blew up on them. I know, this is probably heresy but if you think about it we probably don't have a ton of data on the effects of bad gear setups. It's all anecdotal.
 
Sometimes you just get lucky. I put carrier bearings in a chevy truck that had deflected so far it chewed a third of the ring gear tooth face off. 10 years later it is still running around
 
hear said:
I drove it 50 miles on the highway at ~70mph & then around town for a couple weeks, all apparently in this condition. Somehow it was fine. I would LOVE to know (a) how long it was like this and (b) what the long term effects would be. Don't get me wrong, I'm absolutely doing the repair. But at the same time it strikes me as odd that setting up gears requires this precise alignment but then I can be this far out and now show any real effect.

Maybe it wasn't enough miles or time, or maybe it only really creates a problem under hard acceleration? Or maybe the precision doesn't matter quite as much as legend would have us believe? Hard to say, since 99% of gears out there were set up professionally or done by people where who took great effort to get good patterns, and the remaining ones are shade tree bubbas who most likely aren't going to report that their "just send it" gear job blew up on them. I know, this is probably heresy but if you think about it we probably don't have a ton of data on the effects of bad gear setups. It's all anecdotal.
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I don't think it's as scientific as the internet wants you to believe. Obviously, doing due diligence for a proper pattern, preload, and general setup will yield the absolute best chance at success, and that is how it should be done. But there is probably plenty of negligence out there that still somehow still gets by with little to no issues. I watched a dude on YouTube setting up a Dana 35 and he did not torque a single bolt, he didn't measure backlash, he didn't use any pinion depth shims, he didn't measure the carrier shims, he used the crush sleeve during set up and also installed the seal during setup. He threw the new carrier in there and stuck a stock shim on either side. Ran a quick poorly executed pattern and said "that's great, I like that" (and it was not a proper pattern, it was shallow due to no pinion shims). Dude absolutely just sent it. So far no word on it failing and that was a year ago. He also spun the diff probably 30 miles per hour with his impact wrench on the pinion and with no lube. The whole video was very hard to watch. Of course, if it did fail, he probably wouldn't post about it.

It's definitely best to do the best work you can, but ultimately if the teeth are meshing it will probably take a whole lot to blow the setup. I'd imagine you're more likely to get a defectively made gear that gives up easily. Most people who have an all out diff failure also seem to have had things like spider gears or other small parts fall apart and chunks ended up where they shouldn't be, like in the bearings or in the gear teeth. It seems quite rare that actual failures happen from poor setup itself. Not to say it can't happen though.
 
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I had a garbage shop set up my 8.8 and regear my Dana 30 back in 2016. Dana 30 pinion slop, gear noise, and when you took the cover, the diff would plop out on to the back side of the tie rod. This past fall my buddy brought over some shims, a new crush sleeve, and a case spreader. Added every single shim he had lol, but everything is now to spec, noise, and slop free. It survived a very long time way way out of spec. I will always endeavor to get it done properly, but it's not the critical to life rocket surgery people make it out to be I think.
 
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Got everything out. The carrier bearings felt a little sloppy, but the pressed on pinion bearing was a mess. The cage had a ton of slip in it, not sure if the pictures really do it justice. But without much effort at all I can almost get the cage over the rollers. The other bearing was a-ok.

BC0D3176-1D98-4CD2-ABA5-0DC47E33EFAC.jpeg


Then just for kicks, a comparison between a 4,10 pinion and a 3.07 pinion. I can’t imagine how small a 5.38 pinion would be.

BB2F81A7-84C1-476F-8D7A-57D5B6D047BA.jpeg
 
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hear said:
Got everything out. The carrier bearings felt a little sloppy, but the pressed on pinion bearing was a mess. The cage had a ton of slip in it, not sure if the pictures really do it justice. But without much effort at all I can almost get the cage over the rollers. The other bearing was a-ok.

View attachment 510656

Then just for kicks, a comparison between a 4,10 pinion and a 3.07 pinion. I can’t imagine how small a 5.38 pinion would be.

View attachment 510657
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Nice. The 3.07 pinion is massive but remember it has a different carrier that mounts the ring further away. 3.55-5.13 all use the other carrier and all have similar sized pinions. So 3.07 is the lone wolf on giant pinions and that’s because the pinion needs so many teeth to make a 3.07 ratio.

Out of the 3.55-5.13 pinions, 4.88/5.13 are same size and slightly smaller than the rest. 5.13 uses an identical pinion size and tooth count as 4.88, just with a different tooth profile. To go from 4.88 to 5.13 they just add 2 teeth to the ring and rework the profile a bit.

No 5.38 offering for Dana 35. I think the gear manufacturers weren’t comfortable offering that on the Dana 30 or 35 sized rings.
 
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I think y'all are fooling yourself that this doesn't need to be as accurate as it should be. Are there R&P's that survive bad setups? Sure. But you don't see any videos of the same people who posted the crappy setup when it fails. Plus the noise that comes with a bad setup along with the peripheral damage when it finally fails. Dana 44 housings are already hard enough to come by, why take a chance on damaging it beyond repair? FFS if you're in there to do the work, do it right.
 
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hear said:
Got everything out. The carrier bearings felt a little sloppy, but the pressed on pinion bearing was a mess. The cage had a ton of slip in it, not sure if the pictures really do it justice. But without much effort at all I can almost get the cage over the rollers. The other bearing was a-ok.

View attachment 510656

Then just for kicks, a comparison between a 4,10 pinion and a 3.07 pinion. I can’t imagine how small a 5.38 pinion would be.

View attachment 510657
Click to expand...

The cage will be loose on a new bearing until it has a load on it.

Your pinion bearing is TOAST. Which means your others aren't far behind. The pinion gear looks ok from the little bit I can see. I would replace the four bearings, seal, and crush sleeve and call it a day. Put all the shims back exactly where they were when they came out. With new bearings, you'll want the pinion pre-load set around 16-20 in/lbs. Note that it's not ft/lbs. You'll need a beam style torque wrench to measure this.
 
hosejockey61 said:
I think y'all are fooling yourself that this doesn't need to be as accurate as it should be. Are there R&P's that survive bad setups? Sure. But you don't see any videos of the same people who posted the crappy setup when it fails. Plus the noise that comes with a bad setup along with the peripheral damage when it finally fails. Dana 44 housings are already hard enough to come by, why take a chance on damaging it beyond repair? FFS if you're in there to do the work, do it right.
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Who’s talking about not doing it right? I said earlier I was replacing all the bearings, as in your Dana35 video.

I’m just questioning the *need* for all that precision when I can have this much slop for this long and have it make no noise and show no ill effects on the gears themselves.
 
hosejockey61 said:
I think y'all are fooling yourself that this doesn't need to be as accurate as it should be. Are there R&P's that survive bad setups? Sure. But you don't see any videos of the same people who posted the crappy setup when it fails. Plus the noise that comes with a bad setup along with the peripheral damage when it finally fails. Dana 44 housings are already hard enough to come by, why take a chance on damaging it beyond repair? FFS if you're in there to do the work, do it right.
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I don't think anyone is suggesting to intentionally do it wrong. There were a few suggestions from some to cinch up the nut if it was loose, but it wasn't loose.

The plan seems to be to replace both bearings and run it, and that should work well.
 
hear said:
Who’s talking about not doing it right? I said earlier I was replacing all the bearings, as in your Dana35 video.

I’m just questioning the *need* for all that precision when I can have this much slop for this long and have it make no noise and show no ill effects on the gears themselves.
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I should have hit reply and quoted the previous posts to better explain myself. My point is, if you let it get in your head that it's good enough, that's when people tend to button it up without getting them set the best they can be.
 
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My comments might have been unclear as well. I in no way advocate setting them up without doing everything correctly. I meant I was surprised things can stay alive longer than I thought when things are buggered up.
 
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Mike_H said:
it’s all a case of just because something works, doesn’t mean it’s right.

A
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Everyone is going to ignore this after they read the rest so I'll put it first: I'm not advocating not doing it with precision. I think it's a good idea to be as precise as possible. However...

It doesn't mean it's wrong either. That's kinda my point. 99% of cars haven't had their rear end touched after it left the factory. Of that 1%, 99% of gear jobs posted here & elsewhere online are highly attentive to detail. That 1% is Bubba doing a sloppy job in his side yard and (a) he's not going to post it on a forum in the first place and (b) you're probably never going to hear about it being successful/disaster even if his install video has 1M views.

I'm just saying there isn't very much data on bad gear jobs to really even say what a bad gear job is or how it will turn out. And consider that for the most part we're just doing what the FSM says & remembering that amateur mechanics everywhere repeat the mantra "gears are hard, you have to take them to a professional" which further feeds into the philosophy that they must be done with precision. You'll read (even here) that a bad job will be noisy or wear prematurely or whatever......what % of people stating those 'facts' actually have any firsthand experience to back it up? I'm sure hosejockey does, and probably some others. But I'm confident the vast majority of advice or horror stories are second hand.

But we'll never know for reasons stated above, and while I'm willing to buy Autozone parts and admit it here, I'm not willing to do a sloppy gear job and share it here because ultimately I've bought into the conventional wisdom too. And when I inevitably need help later I don't want to deal with "aren't you the idiot who didn't think backlash was important?" Of course that's all anybody is going to remember from this brief essay anyway.
 
hear said:
Everyone is going to ignore this after they read the rest so I'll put it first: I'm not advocating not doing it with precision. I think it's a good idea to be as precise as possible. However...

It doesn't mean it's wrong either. That's kinda my point. 99% of cars haven't had their rear end touched after it left the factory. Of that 1%, 99% of gear jobs posted here & elsewhere online are highly attentive to detail. That 1% is Bubba doing a sloppy job in his side yard and (a) he's not going to post it on a forum in the first place and (b) you're probably never going to hear about it being successful/disaster even if his install video has 1M views.

I'm just saying there isn't very much data on bad gear jobs to really even say what a bad gear job is or how it will turn out. And consider that for the most part we're just doing what the FSM says & remembering that amateur mechanics everywhere repeat the mantra "gears are hard, you have to take them to a professional" which further feeds into the philosophy that they must be done with precision. You'll read (even here) that a bad job will be noisy or wear prematurely or whatever......what % of people stating those 'facts' actually have any firsthand experience to back it up? I'm sure hosejockey does, and probably some others. But I'm confident the vast majority of advice or horror stories are second hand.

But we'll never know for reasons stated above, and while I'm willing to buy Autozone parts and admit it here, I'm not willing to do a sloppy gear job and share it here because ultimately I've bought into the conventional wisdom too. And when I inevitably need help later I don't want to deal with "aren't you the idiot who didn't think backlash was important?" Of course that's all anybody is going to remember from this brief essay anyway.
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What is interesting is that my last two trucks (an 02 avalanche and a 14 F150) have had the rear diffs go out, on factory set-ups. The chevy had about 150K on it, so not too bad. The Ford lost a pinion bearing about 50K miles in and they (Ford) ignored it until it grenaded the whole thing at 61K. I cringe when I see guys like Fab Rats and Matts Offroad.... slap things together and say "good enough." They might have enough experience to do that and they know if it blows up, they have another Video they can make. Nearly everyone watching that video doesn't have that experience though, but will take what they say as gospel and run their own junk that way.
 
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