Rear differential leaking?

[92LongBed]

Noticed a bit of fluid in my driveway after running an errand today. Not sure where to even begin diagnosing. Anyone have any idea why my undercarriage is coated in oil spray? Bad seal from my driveshaft to rear axle diff? Pictures below. My muffler has spots where there is dark liquid dripping from it as well. near both axles.

I can grab my driveshaft and it twists about a 1/3-1/2" in either direction when truck is parked. manual transmission, not sure if this is a problem or just common function.

It looks like some sort of grease or oil is being flung from my driveshaft all over the underside of my truck.

You must be registered for see images attach

You must be registered for see images attach

 

[lsaami]

Looks like your pinion seal bit the dust.

I’m not familiar enough with these axles to tell you where to start on replacing.

 

[Nero]

Replacing the pinion seal is pretty straight forward.
Bust nut off flange, take flange off. R&R seal. Replace crush sleeve. Torque flange back on. Have a beer.

 

[Cant Write]

When we did my ‘91 suburban 3 years ago. (14-bolt semi-float)

We jacked the wheels off the ground before doing what Nero said. And also used a “speedy sleeve” as I have a groove.

 

[Austin86250]

Make sure you set your pre load right i didn’t and it threw the axle

 

[ROCK HARVEY]

It is your pinion seal, but there’s a good chance your pinion seal went bad because the pinion bearing has play in it. Do you feel any up/down/side-to-side play? When you pull the seal out definitely pull that top bearing as well and have a look at it. Also be sure you know how to set your preload right like Austin said. There are some good YouTube videos on rebuilding the sterling axles if you decide to tackle it. I ended up buying a used axle and swapping it in when my rear end had problems.

 

[92LongBed]

It is your pinion seal, but there’s a good chance your pinion seal went bad because the pinion bearing has play in it. Do you feel any up/down/side-to-side play? When you pull the seal out definitely pull that top bearing as well and have a look at it. Also be sure you know how to set your preload right like Austin said. There are some good YouTube videos on rebuilding the sterling axles if you decide to tackle it. I ended up buying a used axle and swapping it in when my rear end had problems.

there is no side to side or up and down play whatsoever, and yeah ill need to dial in the preload before I conquer this. i have the new seal ordered so i'll be doing it this weekend.

i've seen a couple vids on replacing on a different axle (8.8) but have yet to see one on the 10.25 ford axle i have so well see.

 

[92LongBed]

Make sure you set your pre load right i didn’t and it threw the axle

Found this information regarding specs for my axle, so I can dial in the preload. Just so i'm understanding this correctly, preload is when i have the axle on jacks the preload is the force i should turn the pinion nut (20-35lbs) and then when truck is lowered onto ground with full weight i go to 150lbs torque? also using loc-tite?

You must be registered for see images attach

 

[u2slow]

Don't crush a new sleeve with old bearings! Those poor old bearings would likely seize or grenade in short order.

Get a crush sleeve eliminator so you can shim and torque it properly. Also check the bearings, they might be at the end of their life.

 

[92LongBed]

Don't crush a new sleeve with old bearings! Those poor old bearings would likely seize or grenade in short order.

Get a crush sleeve eliminator so you can shim and torque it properly. Also check the bearings, they might be at the end of their life.

a lot of new terms for me to digest all at once, ill look into this and check the bearings before throwing it all back together. i want to make sure my repairs last me decades down the road. so ill take all advice

 

[Nero]

Don't crush a new sleeve with old bearings! Those poor old bearings would likely seize or grenade in short order.

Get a crush sleeve eliminator so you can shim and torque it properly. Also check the bearings, they might be at the end of their life.

A bearing will go out if it's bad. I've re-crushed both the one in my truck and the one in my dad's truck he sold. So far, 20k miles later on mine no issues, he had closer to 40k when he sold his standard cab. It's all about the health of the bearings. Without a new crush sleeve, preload won't be set right and that's when things go kaboom.

 

[u2slow]

Pre-loading well-used bearings is playing roulette. They're already broken-in and are happiest with no extra force mashing them together.

The eliminator lets you match the existing crushed sleeve statically and apply full torque to the pinion nut without re-pre-loading the old bearings. I recommend the 2-piece eliminator as the 1-piece can tear up the shims.

SK CSF9-2PIECE Yukon Crush Sleeve Eliminator Kit Ford 9", 9.75", 10.25, 10.5"

SK CSF9-2PIECE Yukon Crush Sleeve Eliminator Kit Ford 9" Ford 9.75" 2010 & older <br /> Fits models 2010 & older<br />

www.drivetrainamerica.com

 

[Black dawg]

The crush sleeve doesnt create any pre load on the bearings. It is just a squishable shim pack that can take a certain amount of pinion nut torque without collapsing. Without it you would be tightening the pinion nut up against the pinion bearings and could only go to very low torque to have correct bearing pre load. and would be impossible to keep the pinion nut from coming loose.

As far as trying to set preload with the carrier still in the diff, would be impossible to measure it, someone who has done many could have a feel for it, but for someone who has never done it......no.

 

[Rdnck84_03]

I known this technically isn't the correct way but I have installed a lot of pinion seals without replacing the crush sleeve as long as the pinion isn't loose prior to tear down.

James

 

[Black dawg]

Crush sleeve never gets replaced when doing a pinion seal.

If you are not familiar with the job, marking the pinion nut in relation to the pinion shaft can help. Sometimes when tightening the nut back up the crush sleeve will squish some, takes a little bit of feel to avoid that happening. I usually clean the threads up and use a good loc tite, and not get crazy with the impact.

I do agree that the crush sleeve eliminator is awesome, and I hate crush sleeves as much as anybody, but used carefully and correctly they do the job.