Alright so over the fall i blew the rear end up in my girl friends k5 blazer off roading it. I finally got around to addressing the issue or atleast in the process. I got the carrier out the pinion and cleaned it up. Im picking up a gear set from a local and this is my first gear set replacement. i would send it out to my local olds guy but As the truck is off roaded and the braked lines are a real p.i.t.a i opted to tacke it and do it on the truck. Now i already have read to just not use the pinion depth tool and just go buy the wear patter shown by the compound. now i do know what to look for in the patter . I used to make ring and pinion sets but on a much bigger scale. My real area of concern is the crush sleeve/ shims. Do is start with the o.e. and shim it or use a new one hwo do i go about it . This is like a gray area for me. Also does anyone know what the pinion get's torwued to on a 91 k5 blazer I do not have a repair manual. Any help is gretaly appreciated and will avoid my gf giving me crap for putting off till now when we are suppoused to get snow soon. She likes he 4wd .

 

When you are doing the trial & error mock-up,to check for pattern,you don't need any crush sleeve at all.I would start with a pinion shim around .035".Shim the carrier to achieve .008" backlash,and see what the pattern is.Once you get the ideal pattern,take it apart one last time,install a new crush sleeve,put some white thread sealer on the splines,to prevent fluid from wicking through,and red lock-tite on the nut.

 

How much will the sleev crush. If I understand correctly. I use shims to get the ideal backlash and pattern. Now do I use those shims w/ the. Crush sleve or do I tighten the crush sleve to the desired backlash and mount distance on the pinion.

 

I'd venture to guess that it takes around 250 lb. ft. to crush the sleeve. Once you feel the sleeve crush down, You must keep tightening until you achieve the correct drag on the yoke. Use an INCH lb. torque wrench. I scoot it back and forth and like to get it around 25 lb. in. It should feel like a tight doorknob when you turn it by hand. I also use the red loctite, and use a punch on the nut to mush it into the threads a little bit so it won't back out. Easiest way I've found to do this under the truck like you plan to do, is to slide a long pipe wrench over a strap style yoke, and let the handle rest on the ground. Then get a big cheater bar and give er' hell.

 

The crush sleeve is not needed to check or achieve your desired settings & pattern.Install it when you are done.

 

J i'll tell ya what. You want that cam i have . Give me a hand setting this rear end up and it's yours free.

 

Crush sleeve is to keep the pinion bearing preload it keeps some tension on the pinion nuts to thread contact. This is why ...really you should never back off the pinion nut. BUT the lock tight and the staking of the pinion nut with a punch will help keep this nut from backing off under high load torque conditions.

The pinion shims (small diameter shims) are for setting pinion depth and will help get your pattern with the ring gear correct. With GM gears .038 will be the best bet to start and with aftermarket gears .035 as Brian stated would work well to start.

Carrirer shims - (larger diameter shim that will be placed on either side of the carrier bearing in the bearing cap saddles. ) These shims are used to set the backlash (drive side to coast side slap) IE so when you rock the ring gear forward and reverse and you here a click ...this is your backlash and MUST be measured with a Dial Indicator (magnetic base unit can be gotten at most Harbor Freight for pretty darn cheap) Good backlash can be between .005-.010 ( .008 .009 .010 will be best for checking the pattern of the gears set)

Try to use the thickest carrier shims to get your backlash IE (if you need a .250 shim pack do not use a .240 and one .010 it will be tough to drive the carrier shim in as you will have a very tight spec and the .010 will probably bend and not slid into the saddle.)
Use .200 and a .050 that will work better for you to tap into the saddle .

So as Brian siad after finding the correct pattern Clean all your components and do your final assemble using the NEW seal crush sleeve and PINION NUT.

A honed out bearing for the pinion REALLY will help the back yard builder as the pinion bearing cage can be compromised after any installs and removals.

You can send pictures and will all help on the pattern for you also.

I have a site that does this also - if that helps.

Take care and GOOD LUCK! It does help to have someone with you that has a clue as to how all this goes. More eyes will help on the pattern too. Jim mitschke

 

Thanks monza that was some great info. I know what the pattern should look like I'll post pics anyway. The machine shop I worked for made and tested ring and pinion sets up to 120 inches in diameter.

 

Ok i thought i would follow up to this. So i finally got a ring and pinion set thanks to sickyolds and i got a pare bearing to hone out thanks to j-chicago . I just got my installation kit and the richmond dvd install . it really helps to have something to watch as it makes what you guys have said make much more sense. Now i have one question. I noticed in the video the used an impact on the preload check. Now i know I should not just drive it in but probably goose it untill the preload it proper. How do you guys feel about this. Im thinking firday will be nicest day of the week so im probably going to do it then.

 

I torque the ring gear to carrier bolts in a star pattern like a spare tire. 65 lb ft.

As far as the carrier bearing caps, I usually just go to 45 when I'm setting it up, and then loctite and go to 60 on the final.

The pinion i do with a battery impact, that gives up on bolts at around 90 lb ft.

That's just me though. I'm no pro, just a shadetree guy with a few ounces of common sense.

Here's a picture of how my pattern ended up.





I picked up this gearset from Monzaz, and was very happy with how it laid out for me.

 

Hey every bit helps. I created this thread with little info and now i have enough to feel confident in what im doing.

 

Good thread copper...I'll have to refer back to it when I do mine as well, just as soon as I recover from my AR purchase lol!

Brian already sent me the spec sheet for a set of moser axles for the 8.5" a year ago, still have that email...thanks Brian!

 

I think the questions i had make the thread good lol . Since i have some understanding on the topic these guys have guided me in the right direction and will help anyone with a good to decent understanding on differentials compared to questions asked by people with little to no understanding which all i found was beginner info that didn't get very indepth into the subject. I looked around but i could not find a thread that would answer what i needed to find out. Again to all the guys who contributed you guys really explained eveything very well.

 

Ok here are some things I noticed and read-
Do not use lock tight on the main cap bolts for the carrier only oil.
ring gear bolts DO GET LOCK TIGHT. It is also a good Idea to progress the torque on the bolts in increments also like 30 ft lbs 45 foot lbs then 60 fott lbs. In the lug tighten sequence like your doing.

Impact- there is NO torque rating for the pinion nut. It is what ever it takes to crush the crush sleeve. DO not back off the pinion nut. You have to creep up on the preload. If you go past...Well that is about it. Try again with another or remove the crush sleeve and tap it on the pinion till you get some few thousands back to try again. (This is what we would do at the track if some one lost a ring and pinion and we had time to set it up with another...Usually a 3-4 day race... Jim

Oh the Pattern you have pictured. Look good over all but might be better with about .002 less pinion shim. Little bit deep in the valley on the drive and coast side.

Great Job on the set-up over all.

Jim
JD

 

Thanks jim. I don't loctite the ring gear bolts, and the 90 lbft on the pinion is only for setup, and not final.
Final is a LOT more when you have to crush that sleeve.

 

Does anyone have a spare bolt pin for the pin that holds the spier gears. Mine broke when i took it out. If that makes sense it's the bolt that you take off to take out the pin to push the axles in to take out the c clips. I need one and right now it's freaking freezing to go looking in the wrecking yard. Any help is appreciated.

 

Ok following up i got out today and started setting it all up. Not nearly as bad as i thought. I got a pattern similar to what J posted up . Im going to mess with it some more and see if i can get a better pattern just to mess with it. I got my back lash at ten thousanths . I know i can tighten it up a bit but im very close as is now. I am measuring my shims so i know what goes back in and i dont have to guess again. hopefully i"ll warp it up this saturday night. I also gotta thank J for texting back and forth and helping me out. I also gotta thank all you guys who contributed with information it really helped out. I dont think i got one bit of bad info or info i did not understand.

 

If you can post a picture of the pattern,I can tell you which way to go with it.

 

Thanks 507 I'm going to try to get it better on my own. Just to see what I remembered from working at the machine shop. Then I'll post and see what you guys think. This is one of those situations where I want to see what things do and I do other adjustments as I also plan on doing the diff in my dads car. I'll check back in in a few days.

 

YOU DO USE loctite on the ring gear bolts NOT the carrier caps bolts.

Set- up 90ft lbs. is too tight on the bearing how can you ever turn the pinion??? Just snug up the pinion bearings into their races and oil them. NO CRUSH SLEEVE YET NO SEAL EITHER. Not until you get the pinion depth correct.

Sorry, I just want the forum to have the correct info - I am not trying to **** anyone off or step on toes. Thanks, Jim

 

I ran my pinion nut in with the impact. I tightend it up untill the bearings where seated, and the pinion did not have any back and forth slack and moved freely. The pinion shaft was actually a few thosanths too bigh I had to polish it by hand with 180 grit and oil to get the bearing behind the pinion to slide in snuggly like the original one. I compared the diameter to the original one it was about 3 thousanths too big. I didn't bother measuring to see if I made a diffrence just wanted the bearing to go through with out having to whack it in. It has to be pushed in with some force but is not loose to where one can push it in by hand. Btw brand was superior.

 

No pissyness here at all jim. thanks for helping everyone out. I was merely making a point that 90 lbft doesn't necessarily guarantee the crushing of a new crush sleeve . Someone might have easily stopped at 90 and never crushed the sleeve.

 

Here is a pic., my application of the compound was a bit sloppy but you can make out the pattern. You came make out the pattern n the
coast side atleast i hope you can make out the pattern it's kinda overexposed due to my halogen work light but its down there lol.

 

on this one you can make out the drive side. this was the pattern at ten thou backlash .i have not messed with it since .

 

Your definitely on the right path. Usually it does not matter where and how you put the compound on the teeth both sides evenly and completely. I usually try to do almost all of them to see if the gear has any run out of the pattern. IF you use the gear oil after the pattern has been run a few turn it will help the teeth really show the pattern . Another help is drag to the ring and twist the pinion so it really bites the ring and pinion contact hard...
This makes the pattern more clear and in turn helps to let you know the gear pinion depth is correct and backlash set right.

Forward or backwards the gear should feel the same amount of torque to turn.
Should feel smooth engagement on both ways too.

So if that rear is still open use more compund and oil and see what you get.

I looks very close. What is the pinion shim your using? .030 .035 .040 etc? Jim

 

I'll re check it tonight. The pinion shim I don't know what thickness it is. I started with what came on the factory one. That what I wanted to mess with

 

Do you guys think this pattern will be good enough for just a driver . The truck rarely see's off roading anymore just the typical cruise and trip to the home depot.

 

What is the backlash at? Also with the bearing caps removed can you pull the posi carrier out of the saddles with a tug of the ring gear out ward by hand? IF you can pull the carrier out by hand with out prying it out with a j-bar. The preload is NOT tight enough. Ok? Jim

 

Well got it all done tonight. I ended up re shimming the pinion and got a much better pattern. i drove it around the block i did not hear anything but it's hard to hear a damn think with a loud exhaust and mud tires. But i hear no clunks no gear whinning . Im going to take it for a long drive which i think like a 50 mile drive then cool down then drive again is the procedure ?