Loose pinion

[blazer74]

Do I detect sarcasm? As I stated the nuts are cheap enough and yes if the running torque of a nut is high enough it's fine if not otherwise damaged. ( it's called a little trivia that didn't warrant your response).
And I never said anything about restaking the nut and doesn't even apply to this unless you wanted to damage the pinion threads., and a little locktite never hurt anything on any fastener new or old unless you specifically don't want it.
As far as a statement of pinion being more critical than anything in aviation is a statement that can't even be argued with one that would make if you get my drift. I mean the jet engine installation on a heavy transport aircraft weighing over 300,000 lbs empty couldn't compare to a pinion Nut.
I'm sure you could also compare to a large propeller installation with a torque of over 1500 ft lbs either. There are plenty of preload instances on aircraft. Jack screws, gearboxes ,landing gears ,etc .etc.
Back to your pinion nut of course use a new one, their cheap geeze.
As critical as your pinion is you still didn't replace both bearings and races as in aviation you shall replace bearings and races in a set.
And that pinion nut simply holds the yoke against the bearings and sleeve, the only forces on that nut that could cause it to loosen are centrifugal other than the threads being ripped out of it which ain't gunna happen.
As far as your loose pinion the lock nut is not going to go bad sitting on the pinion, if it loosens thats because it didn't have the proper nut running torque in the first place, or it appears loose because you have wear in your bearings and sleeve.

Have a nice evening and lighten up.

 

[Blue85]

Hey man, sorry if I set you off in my last post. I had no bad intentions and am grateful for your help.

I was not referring to how "critical" the setup is, just that the purpose of crushing the sleeve and then holding the correct pressure in a diff is kind of a specific application, so a rule of thumb developed for something else might not apply. It does make sense that a certain amount of friction would make it OK, I just don't know what that number should be. I worked in automotive and I work in aviation now, so i understand that the requirements are much more stringent for the latter - no argument there.

There's only a few reasons I can think of for a pinion loosening up:
-Races were not fully seated when diff was assembled
-Crush sleeve was damaged (maybe yoke was smashed on a rock?)
-Bearing or race is very worn
-Nut wasn't torqued properly to begin with

Now if the nut could get a little loose, I can see some pinion movement continuing to make things looser. I would imagine that if the races weren't seated, the problem would have shown up sooner - not after 5 years of use. If the bearings wore away enough to let it get loose, that should be very noticeable. Bearing wear will reduce pinion preload over time, but shouldn't let it get sloppy. Improper initial nut torque seems almost impossible to me when it was just used to crush the crush sleeve.

What I do know is that stories pop up here from time to time of people finding loose pinion nuts - so for some reason it happens.

 

[blazer74]

I seriously doubt the nut loosened, there are really no extreme forces on it to cause it, nor vibration unless the nut had bad locking friction which I'm sure is not the case.

The reasons you stated , seating races, wear or a rock strike damaging the crush sleeve are probably why you had slop.
Does seem a little quick for wear tho.
There isn't very much preload involved so it wouldn't take much to create looseness.

I've had a 12 bolt do the same thing, tightened back up and drove it for years.

Those bearing cups for installing the races come along on eBay, I have a set for the 9.5 but haven't put it together yet .

Outer bearing, sleeve and seal and you'll be fine but it wouldn't hurt to look inside and make sure nothings else is loose or damaged.

Good luck.

 

[Blue85]

I started looking up dimensions to see if the CSE for some other axle might work.

Small (outer) bearing IDs:
10-bolt: 1.625
14B SF: 1.875
14B FF: 1.75"
Dana 60: 1.625"
Dana 70: 1.75"
Dana 80: 2.0"

So what else is there? It turns out that a variant of the Chrysler 8.75" diff is a match

Chrysler 8.75: 1-3/8" (41 Case)
1-3/4" (42 Case)
1-7/8" (89 Case)

The problem is that the "489" axle has a super long crush sleeve. Here is the CSE kit for it:

Since it has a taper, it's unknown which diameter the shims are. If they are for the 1.875" part, that sleeve could just be cut down to the right length.

It looks like that axle calls for an 88048 bearing, which has 1.312" id, but looking at the picture of the tapered pinion the shims may be on a 1.875" section.

 

[Deuling]

What's wrong with a crush sleeve? I really didn't find it that big of a deal to do on the 3 axles I just set up. Even the 14bff wasn't bad.

 

[dyeager535]

Not that this helps, but wasn't there a sort of rash of the 14SF pinion nuts coming loose for seemingly no reason on factory setups? IIRC it was with the later trucks (late 80's or 90's).

 

[Hogback Fabrication]

What's wrong with a crush sleeve? I really didn't find it that big of a deal to do on the 3 axles I just set up. Even the 14bff wasn't bad.

If you load the diff hard enough, they'll crush after they're installed and you'll lose all of your pinion bearing preload. 9" Fords are probably the worst (if you see one of their crush sleeves you'll see why). Never seen that issue on the 10.5" 14 bolt, but I never feel bad about getting rid of a crush sleeve. Crush sleeves are just a short cut by the factory to make diff setup faster.

 

[Blue85]

Plus with the shims you can take it apart to change the seal (or whatever) whenever you want with no worries of changing the preload.

Granted, the seals fail a lot more often when the pinion gets loose, but that's still a win if it never does fail.

With the CSE and a lubelocker, differential service gets a lot easier. (Yes, yet another product not available for 14B s/f).

 

[Deuling]

So get the measurements while yours is out and have someone start making one

 

[blazinzuk]

What measurements does someone need I bet I can find some shims that will work its just gonna be spacer itself

 

[Blue85]

I can find a machine shop or somebody with a lathe to cut tubing, but you can't just grab tubing in any diameter you want. That's why I thought maybe the Chrysler kit would work - just cut that spacer a little shorter than my last crush sleeve was and use their shims.

The ID is just a little bigger than the bearing ID. The OD needs to be less than the race. Those are basically all the measurements.

 

[Blue85]

Knocked out the old race - it's not too bad.

Got the new stash of parts:

It seems like RockAuto has the best prices on Timken. $5.56 and $10.95 for race and bearing. Due to double/triple shipping costs I got the seal, nut and crush sleeve locally - just under $20 at Autozone - special order from Yukon only. This seemed a lot better than the "minor install kit" that sells for $80 to $105 from various vendors: http://www.ringpinion.com/b2c/ProductDetails.aspx?ProdID=2620&Product=MK_GM9.5-B&Brand=Yukon_Gear_and_Axle


The weird thing I found today is the chipped magnet. I've cleaned the axle tubes and housing, but will now also go through the diff carefully to look for any debris.

 

[Blue85]

I wasn't sure where to set the pinion preload with one new bearing and one used, so I put it at about 12 in-lb. I was expecting to use the same shim settings as before all around, so I went ahead and set the bearing preload without even checking the depth shims. The pattern was fine, but the backlash was too wide (about .014). I had a hard time adding any shims to the left side of the carrier without going past zero backlash, but eventually found a combo that gave about .007. The pattern still looked good:

Now the diff is done, so you can all sleep easy.

 

[rebelgregory]

good deal. If it was mine, the gov-loc would let go tomorrow. Hope you have better luck.

 

[pblaze725]

Interesting read. Now I know what went wrong with my 10 bolt when I swapped gears.

We did it all wrong.