Rear Diff Yoke Installation

[Thundergun]

Hey Guys. Sorry if this topic has been discussed previously. I did some searching, but couldn't find what i was looking for. I was pointed to a thread from 2009, but when i went to reply it was recommended to start a new thread .. so here goes.

So i swapped my '85 k10 short bed 10 bolt for a 12 bolt. Wasn't aware of the needed u-joint conversion and thought i could swap the yokes on the diffs. No way. So i removed the yoke from the 12 bolt, and now i need to put it back on. Have the u-joint convertion in hand. How do i re-install the yoke correctly?

I found this quote from Vile from 2009. Can anyone please elaborate a little? Why do the axles and diff carrier need to come out? do i  need a new crush plate? i didn't notice one when i removed it. Why can't i just torque it back on with the breaks on to keep the axles from moving?

What bearings need to be properly preloaded? Is this easy to do?

You need to witness mark the pinion nut to the yoke and to the pinion shaft before removing it. The only way to properly retighten the nut is to remove the axles and the differential carrier. Then you can measure pinion turning torque to know if the bearings are properly preloaded. Otherwise at this point you're pretty much guessing.

[pholliday1]

Yea..... many a differential has been ruined by the unknowing of "I'll just torque the nut down" I'll try and keep it simple think of bearing preload as the amount of resistance it takes to rotate the pinion and is measured in inch pounds ...more specifically a torque wrench that uses a needle pointer and not a "clicker type" and this is all measured without the additional resistance of the diff carrier. You measure the resistance that it takes to keep the pinion moving not how much it takes to get it started moving. Ball parkish like 12inch pounds for used bearings and like 20 inch lbs for new bearings. These are just examples IDK your actual numbers.  Anyways what happens? "if I just wing it" well at first it will work fine but then if there's not enough preload the nut will loosen and if its to tight you'll burn up the bearing and if you over crush the crush sleeve and get to much resistance then you have to take it all apart and start over with a new crush sleeve.....That's why to really get an axle setup "RIGHT" is really takes some knowledge and special tools however, with that being said it can be done...good luck!

[Thundergun]

alright thanks a ton for the info. Much appreciated.

Sorry but ... more newbie questions..

How do i remove the carrier? Is it fairly straight forward. I do have the chilton manual for reference.
Do i need to remove the axles? if so how?

Thanks for your help!

[Captkaos]

Remove it to replace the crush sleeve?  If you have no knowledge of setting up gears, you are asking for trouble unless you have the right tools.  This like replacing an intake.  There are strict tolerances involved.

[hatzie]

Not a simple job.  I've done two 14bolt GM rears and Dana 60 & 44 fronts. The 14 bolts were easy.  The Dana s were very fussy.
You will need an in/lb torque wrench to measure rotating pinion preload.  The carrier and axles will need to be removed so the pinion is floating...not engaging the ring gear.
You will need a couple new crush sleeves.  You wont get it right the first time unless you're darn lucky.   The sleeves crush at something like 300 ft/lb.

Download the GM Unit Repair and Service Manuals. Any of the unit repair manuals will do as long as they cover your axle. The earlier manuals have more procedural details but specs like torques should come from one close to your axle year.



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[Thundergun]

Alright thanks guys. kicking myself in the ass for removing that nut. Sounds like i need to enlist the help from some of my more experienced friends to help me out with this replacement.

It almost sounds like it would be easier to go back to the junkyard and get another complete rear end for $200.

I'll see if i can find the GM Unit Repair and Service manuals.

[hatzie]

My Pdf scans of the GM service manuals are hosted in the tech section of this board.

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[Thundergun]

Hey guys. Just to reiterate - the only thing i removed was the nut and the yoke held on by the nut. I didn't remove anything else.

My buddy is saying if i tighten the nut back on to 100 ft lbs with some locktite i should be good. Sure sounds tempting.

[VileZambonie]

You should always index the pinion nut, the pinion shaft and the yoke before removing it. You cannot accurately measure pinion bearing preload with the carrier installed. At this point put it back on good n tight and hope for the best or tear down and measure.

[Thundergun]

Thanks Vile. What is the risk of putting the nut on too loose? If we are worried about the nut coming off, wouldn't locktitet take care of that?

[VileZambonie]

The nut is what preloads your pinion bearings. I'd rather see you go a little tighter than too loose. Run the nut down until it's tight and give it a quarter turn, cross your fingers and turn the radio up.