threefivezero

Ok so I learned most of what I need to know by reading other threads here. There's still an area I'm hazy on though.

Situation: 97 7.5" stock rear end with Auburn posi and used 4.10 gears. Growling/howling and after inspection the outer pinion bearing is toast. Everything else looks great. Replacing that bearing and race, and now need to properly reassemble and set pinion bearing preload. Will be using new nut (don't ask) and new crush sleeve.

By reading here it seems that 15in-lb is what I'm shooting for when I reassemble. Here's what I don't know:

1) Is 15 in-lb the torque I want to see required to rotate the completely/finally assembled pinion, *without* the differential installed? So, I'm spinning only the properly loaded pinion in its bearings, without the added drag/weight of the differential?

2) If 1 above is correct, then how do I know how much to torque down the nut to begin with so that the sleeve crushes properly?

3) How do I do 1&2 so that I can also get thread lock on the nut without the thread lock starting to harden during the whole process, and therefore messing up any measurements I make on torque?

The reason I'm doing this now (again) is because I just eyeballed/felt/guesstimated it the last time I put it together. I want to be sure I understand it this time so that hopefully it will last long enough that I can save for an 8.8 build. I clearly didn't do it right last time.

flintwrench69

iTrader: (11)

That would be without the diff installed. Thats with used bearings but youre replacing one of the bearings so I would go with the 15-30 in lb spec for new bearings.
If you have a 1/2 in drive impact you can gradually tighten it with that until proper turning force is achieved. Or use a big breaker bar & holding tool for the pinion yoke.
Threadlock will not dry that quick.

threefivezero

Cool I think I've got it now, thanks!

I found a youtube video of a guy doing a similar rear with a crush sleeve. I think what was confusing me was that you need massive torque to crush the sleeve, but then are measuring the final product in inch-lbs. So, the torque required to crush is actually torque between the pinion shaft and the pinion nut, where the 15-30 in-lbs is only the torque required to 'free-spin' the completed assembly?

flintwrench69

iTrader: (11)

Pretty much, the pinion nut is tight enough if it takes 15-30 in lbs of torque to turn it.

LQ4Supra

iTrader: (1)

I am not intending to hijack, but this is a lot of what I found searching and answers part of a question I had as well. However I have a pair of slightly different, but related questions. I'm actually replacing my pinion seal right now and I hit a snag. Maybe I can get a little clarification.

1) Preload is determined with an assembled differential, but does that mean those numbers are good with just the tires off or do I need to pull the axles to measure preload correctly?

2)Should there be any wobble in the yoke?
I measured the total depth of the assembly before and then tightened to the original depth and the yoke wobbles slightly (maybe 1/8" side to side). I think that it should have little if any wobble/deflection in the yoke but it doesn't want to tighten any further inward and I am afraid of over tightening the crush sleeve. Since Alldata doesn't even give preload numbers, it says it should come in another 1/16th of an inch from my initial measurement but it doesn't want to come in any further.

I don't want to damage the crush sleeve but I don't want my pinion climbing my ring gear either.

01ssreda4

iTrader: (96)

I've never used thread locker. The nuts have dimples punched into them preventing them from spinning themselves back off.

threefivezero

I just finished this today. A couple things I learned:

I don't see any way to do this under your car in your garage. You'd need a hoist. I couldn't get the car high enough in the air to use a long enough bar to get enough torque on the nut to crush the sleeve. Even with the car 3' in the air and a bar reaching out from under the car, the rear end can flex in the suspension too much to get a real 'bite' on it. I ended up completely removing the entire rear end and doing it on the garage floor.

Thread lock sets up in about 30 minutes. Not completely, but enough to mess with your torque. So, once I realized I couldn't do it properly, and I tried to get the nut back off before the thread lock dried, it was too late and I couldn't even remove the nut with an impact gun. flintwrench69 is right- the thread lock won't dry fast enough to cause you problems if you're doing it right! But, if you have trouble, your window is limited. On the garage floor I had it accomplished in under 15 minutes.

threefivezero

My understanding is that you need to measure the torque on the pre-loaded pinion with the differential completely removed. (So you're only spinning the pinion shaft and gear in the pinion bearings, nothing else.) You may be confusing (like I did) the setup/pre-load of the differential bearings with the setup/pre-load of the pinion bearings. But someone please correct me if I'm wrong about that, I'm new at it too.

Ok so here are a couple things:

For sure, absolutely no wobble. If it has even a hint of 'play' in any direction (into/out of the houseing, or side-to-side) it isn't set up correctly and you can measure the remainder of your rear end's life in feet if you drive it like that.

I'm not sure if you're reassembling a used setup after replacing only the pinion seal? Or new bearings as well? In either case, here's my advice: I spent all day today doing it right the third time because the first two times I just got it close and hoped for the best. If you disassemble the pinion nut, my advice would be to take the whole thing apart, use a new crush sleeve and new pinion nut, and set it up all properly. I think the enemy here is that the crush sleeve is really only intended to be used once. If you disassemble then try to reassemble 'where it was' by either counting threads or measuring depth, I don't think you'll ever get the preload right. I certainly couldn't. Essentially, once you 'unload' the crush sleeve, you can't 'reload' it properly. Doesn't work that way. You might get lucky- the first time I reassembled mine with a used crush sleeve it lasted about a year before it came loose. Maybe other people get even luckier, I don't know.

threefivezero

^^^absolutely true. However, once you run the nut down on the pinion once, the shaft 'bores out' the dimples and it ain't a lock nut no more if you remove it. So, if you do it right the first time, you're golden. The new nut is about $4 so I'd say buy 2 just in case.

I used thread lock anyway on top of the new nut. On my 2nd half-arsed attempt the pinion nut came loose within 24 hours and it was a most unpleasant ordeal. However, keep in mind that if you use red like I did, you need a torch or about 500 ft-lb of torque to remove the thread-locked nut. If you used only a new nut you could probably get it back off with a large breaker bar.

LQ4Supra

iTrader: (1)

Ok, the Haynes manual said I should check the torque required to turn the pinion (Alldata does not mention this) so I was wondering. I am simply changing the pinion seal because it's leaking.

This problem started because the car is at my parent's where there is a carport to work under. While I was welding up a bracket my dad decided to get ambitious and help me move things along. He measured the yoke depth and then tried to change the pinion seal. He came and got me when he couldn't get the old seal out but he had already removed the yoke so I didn't have a chance to check everything else. He tightened the yoke back to the same measurement and it wobbles and he claims that's how it was before but I am certain that it would destroy my ring gear to have any movement. I'm asking to see if I can get this back together without taking it completely apart. My dad is certain it will be fine because "back in the day" when he was a mechanic (he retired in 94) they changed pinion seals like this all the time and none of them came back. I am trying really really hard not to be frustrated at the situation.

Thanks for the help. I know this isn't really related to your troubles.

threefivezero

Maybe you're confusing things the same way I was- When you tighten (torque down) the pinion nut, you're tightening it against the yoke. So, you should be holding the yoke completely still with one big-arsed wrench, and 'wrenching down' the nut with another. This will take a lot of force. I'm guessing by what you've said here, that the nut just isn't completely tight yet and you don't want to put a lot of force on it for fear you'll mess it up.

The force required to 'free spin' the pinion is what you measure as 15-30 in-lbs, and that's different. It's essentially just barely more than nothing. You should be able to 'give it a spin' with your hand basically when it's this tight. When you measure this, you're letting the yoke spin and measuring the torque required to rotate the assembly inside the differential. So, 15-30 in-lb of torque required to spin the pinion and yoke assembly will still have literally maybe hundreds of ft-lbs of torque between the nut and the yoke.

Your Dad is right man- I used to 'back in the day' throw together a ring/pinion out of this truck, posi unit out of that car, fit it all into an Impala housing, never set them up, just bolted them together. For the most part this will work more often than not. A lot of people will argue with me on that but my experience has been that it works fine most of the time.

I just hadn't had much luck doing it that way in this current vehicle though so I wanted to learn how to do it 'right' since I was doing it a 3rd time.

LQ4Supra

iTrader: (1)

Nail on head. I have known of plenty of people who have done it that way, I'm just trying to get this dang thing back together right. I just had to get a pair of new axles and wheel bearings for it because the PO didn't notice the leaking pinion seal and ran the diff a little low on grease. I don't want to upgrade the axle yet because I have a stock motor and am in the middle of a 4L80 swap so funds are tight. Since I sank $300 into getting my original axle spiffy, I didn't want to throw the seal and yoke in at "that looks about right" and get 50ft before needing a new LSD, ring and pinion.