Wobbly Pinion - How is this going to end?

[53lowdown]

62 C10, original rear end. I just started noticing a little bit of whine from the rear - and maybe even some vibration at steady speed. I crawled under and found that I can wobble the pinion about 1/8 to 1/4 inch.

How is this going to end, and when? Is this something that I can drive until I figure out what to do with it? Or is it soon going to shell the rear end soon?

[jayoldschool]

First up, drop the driveshaft and see if you can tighten the nut. If loose, you can get your symptoms. If tight, you need bearings, at a minimum. Drive at your own risk (and wallet damage).

[53lowdown]

Originally Posted by jayoldschool

First up, drop the driveshaft and see if you can tighten the nut. If loose, you can get your symptoms. If tight, you need bearings, at a minimum. Drive at your own risk (and wallet damage).

What tha??? You must be psychic It WAS loose. Is that something that is common? So - do I just tighten it and torque it - any idea what torque? This nut just holds the yoke right? I doesn't affect anything internal?

[jayoldschool]

lol, not psychic, it's just there are only so many possibilities when diagnosing vehicle problems. One starts with the easy/obvious. How tight? TIGHT. I'd put a gun on it and pull it down. Yes, there is a torque spec for it when new, but you're dealing with used components and have been running loose for awhile.

[padresag]

Originally Posted by 53lowdown

62 C10, original rear end. I just started noticing a little bit of whine from the rear - and maybe even some vibration at steady speed. I crawled under and found that I can wobble the pinion about 1/8 to 1/4 inch.

How is this going to end, and when? Is this something that I can drive until I figure out what to do with it? Or is it soon going to shell the rear end soon?

sounds like the bull gear is getting ready to jump the heifer gear.
that is just wishful thinking to just tighten the pinion nut. bearings are more than likely hooped. if the gears are not bad you mat get away with replacing the bearings. I would first pull the drain plug and see how much crap comes out and if there was any gear oil in there. a lot of times rear end failure is due to not checking fluid levels,
ron

[vince1]

Is there not a crush sleeve in those? I've fixed one (non GM) that had a sleeve by changing the seal, putting on a new nut and tightening just to the point of crushing the sleeve again, followed by staking the nut so it couldn't come loose again.

[53lowdown]

Originally Posted by vince1

Is there not a crush sleeve in those? I've fixed one (non GM) that had a sleeve by changing the seal, putting on a new nut and tightening just to the point of crushing the sleeve again, followed by staking the nut so it couldn't come loose again.

Right - I've been looking around and thinking that the pinion nut works a lot like the front wheel bearing nut right? I checked the fluid the other day, and it was low - added a quart, and now it is dripping out of the pinion seal.

But I don't see any crush washer on this diagram http://www.lmctruck.com/icatalog/cbe/full.aspx?Page=92

[padresag]

no the pinion nut does not work like a front w/b nut. it is a lock nut. the only way that it appears loose is if there is a bearing problem which makes the clearance and no gear oil is a way to enhance that clearance;
ron

[Greg63]

The crush is #23 in the diagram.
Greg.

[jayoldschool]

Ah, you left out the leaking part. You need a new seal. I know they make a yoke service kit for the later 8.5" that has a new seal, yoke, nut, but not sure about the 12 bolt. Check rockauto, and maybe Moser.

[53lowdown]

Originally Posted by jayoldschool

Ah, you left out the leaking part. You need a new seal. I know they make a yoke service kit for the later 8.5" that has a new seal, yoke, nut, but not sure about the 12 bolt. Check rockauto, and maybe Moser.

Replaced the pinion seal the other day. Pulled the yoke off and removed the old seal, pulled the front bearing out and it looked ok, the flange looked ok too so put in a new seal, put it all back together, filled with gear lube, and all is good so far. No more noise or vibration, and no leaking.

[jayoldschool]

Good work! Tight on that nut, right?

[53lowdown]

Originally Posted by jayoldschool

Good work! Tight on that nut, right?

Yep, and used red thread locker to keep it from coming loose.

[Modges'66]

Hmmm,
I am not an expert on this, but in theory, doesn't the "crush-sleeve" compress to satisfy a certain amount pre-load on the bearings at a specified torque spec of the yolk nut?
With this in mind, simply replacing the seal, and tightening the yolk nut down with a impact or such on an already crushed-sleeve will result in too much bearing preload. Without adding a new crush-sleeve, you will probably exert too much pre-load on the bearings, and more than likely burn them up in no time...JMO.

[vince1]

Right, you do not want to over tighten it. The preload as I know it is measured in inch pounds. If it were mine I would put the differential on axle stands and see how hard it is to turn. Should be able to turn the drive shaft easily with one hand I would think.