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Discussion Starter · #1 ·
I am getting ready to swap out my carrier and ring and pinions. I am a bit confused about how to find and adjust for my checking distance on my pinion and backlash on my ring gear.

Am I supposed to press off a crush sleeve every time I adjust the shims on the pinion?

Or

Is it possible to get the proper amount of preload without the crush sleeve installed? Then I would just get it set up correctly and use my non set up bearings, crush sleeve, and new pinion nut once I had the proper markings on my ring gear.
 

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I have had good success with 8.5 chevy rears. I've probably built 30-40 over the last 10 years. I think there was only one rear which I used a different shim than what I removed from the original pinion.

My recommednation is to removed the pinion shim from what you've got in the rear already and then see how your back lash is looking.
 

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i rebuild rears alot do yourself a favor use the orig shim behind the pinion bearing and transfer it to the new pinion and install the new bearing or press it on you can do this if your useing orig. housing that shim we'll work just fine for keeping the same depth install your new pinion races in the housing put your crush coller on install the pinion and frnt bearing and seal put your pinion yoke on and take out the bearing play now hook up a tool like a big pipe wrench to the yoke hold it against the springs now take a breaker bar and start tighting the pinion nut you'll want to do this slowly till you get a least an 18 to 22 inch pound reading on a inch pound torque wrench by swinging it back and forth now you have the proper preload set. put your ring gear on your new carrier put your new bearings on set that in the case also you'll want to keep your orig. carrier shims handy make sure not to get them mixed during disassembly keep your left one on the left and the right one on the right put those back in and put your caps on tighten them down snug don't torque them yet set a dial indiactor on the base of the rear put it on the tooth face of the ring gear hold the pinion yoke and rock the ring gear back and forth look at the dial ind. the needle should move back and forth if is dosen't you'll need to chang the carrier shims out and mic them to see what they are to get the back lash set to .008 to .012 lash good luck killer70ss nova:yes:
 

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Discussion Starter · #4 · (Edited)
I have had good success with 8.5 chevy rears. I've probably built 30-40 over the last 10 years. I think there was only one rear which I used a different shim than what I removed from the original pinion.

My recommednation is to removed the pinion shim from what you've got in the rear already and then see how your back lash is looking.
Ok, I will use the original shims. However, When I am checking my gear pattern and reading my marking compound, I have to disassemble everything to get the correct pattern. Does that entail taking off the crush ring everytime? Or is it not necessarily required to put it on while still making the shim adjustments.

Or am I just completely mistaken in thinking that the pinion depth will change?

Here is the step by step I am referencing -- it is kinda unclear if the crush sleeve is required before the final installation: http://www.holdengemini.net/techforum/viewtopic.php?p=289
 

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You should assemble the diff with no crush sleeve until you have the desired pattern then disassemble and install the crush sleeve. This will save you from over crushing it if the pinion shim is not correct the first time. if over crushed you have to replace the crush sleeve.

Miles
 

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This is by no means a tutorial on rears, but I'll simplify this to some basic steps which I seem to have been lucky enough to successfully and quickly set up R&P in the 8.5.

Remove the shim form the pinion gear that was origin to the housing. This is one shim, behind the pinion bearing.

Install the old shim on the new pinon and press on the bearing. Install the new pinion in the rear. I have re-used the old crush collars. To me it really isn't much different than when I've replaced a pinion seal. Mistakes can be made doing that, but I've heard plenty of stories about people messing up the installation of new crush collars too. Your choice, but the bottom line get the pinion installed so you can move on to setting the back-lash.

I drop the carrier in and use the original shims as a basline. Try no to mix them up when you disassemble the rear, but they probably won't be dead-on anyway so not real harm if yo do. Now that the carrier is in, check the tooth contact. Like I said before, it usually is well within an acceptable range. I think this is partly due to the broad design of the 8.5. There is no 4 series carrier on an 8.5. The same carrier that takes a 2.73:1 gear also will take a 5.57:1! Not like an old 12 bolt that used 3 different carries for those ranges.

Once you confirm that tooth contact is acceptable (which confirms you pinion depth is good) you can start shimming the rear to get the back lash into spec. I personally try and stay on the tighter side of the clerance.

Make sure that when you are installing the carrier, the shims are enough of a fit that it will need to be tapped in. I did have a rear which I got into spec and the carrier dropped in smoothly. There appeared to be no looseness side to side, but it did make some noise on right hand turns. I couldn't figure it out, but when I removed and re-shimmed it so that things hard to be tapped in, rather than the easy push I had, the issue disappeared.

I have had great success setting up the 8.5 this way. I wish you the same.
 

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Is it possible to get the proper amount of preload without the crush sleeve installed? Then I would just get it set up correctly and use my non set up bearings, crush sleeve, and new pinion nut once I had the proper markings on my ring gear.

Do not use the crush sleeve until final assembly.
Hone the inside bore of the old rear pinion bearing if in good shape for setup (easy on easy off) . If not usable get a new one and do the same.
Save it for future use, it will also fit a 12 bolt rear end.

I do agree that all the factory shims should be used to start. Sometimes when using a quality ring & pinon set they will be within factory settings and will work out perfect. (I have seen this work maybe 1 out of 100)

You will find that just a few thousand shim can change everything a lot.

Be patient and plan on this being a long process to accomplish correctly. If you get aggravated, walk away and start again when you clear your head.

Hope this helps,
Al
 

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Discussion Starter · #8 ·
Do not use the crush sleeve until final assembly.
Hone the inside bore of the old rear pinion bearing if in good shape for setup (easy on easy off) . If not usable get a new one and do the same.
Save it for future use, it will also fit a 12 bolt rear end.

I do agree that all the factory shims should be used to start. Sometimes when using a quality ring & pinon set they will be within factory settings and will work out perfect. (I have seen this work maybe 1 out of 100)

You will find that just a few thousand shim can change everything a lot.

Be patient and plan on this being a long process to accomplish correctly. If you get aggravated, walk away and start again when you clear your head.

Hope this helps,
Al
This is exactly what I was looking for. Thanks so much for the help
 

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Discussion Starter · #9 ·
Well, I have it all setup (to what seems to be to spec), but I thought I might ask for an expert opinion on my contact pattern. The marking compound is not as clear as I would hoped, but perhaps someone here can tell if it looks good or not.

Here are the pictures of the marking compound: http://s874.photobucket.com/albums/ab305/RyanMoret/Diff Rebuild/

If you can't see something in the pictures, let me know and I'll get some more.
 

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Not the best pattern to read there. What shims did you end up going with?

How much back lash do you have? Do you think you could get the carrier over just a bit more?
 

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Not acceptable.:no:
Pinion is to deep (close to axle center line)
Remove shims at rear pinion bearing.
When you change the pinion shim you will also need the tighten back lash.
This will also help pattern by moving the pattern better in the middle of the root of the gear.
Also a lot of the pattern grease your using can effect back lash settings.

 

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Like stated above don't use the crush sleeve and you can also use your old nut instead of the new one if you have one. I just press the new bearing on with the original pinion shim and check it. If I need to take it off, I have a bearing knife seperator and use that with the press to take off and change shim. As far as changing seals on a built rear-end, I always put a dot on the nut and the pinion shaft for timing marks. When the nut gets close to being tight, I just ease up to the marks I made and go a tad past. This way I know I have the same amount of preload on the pinion.
 

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Discussion Starter · #13 ·
Not the best pattern to read there. What shims did you end up going with?

How much back lash do you have? Do you think you could get the carrier over just a bit more?
I have it at around .005" backlash and am using the original shim (there was only one) on the pinion. As for the carrier shims, the original shims were too wide for for the new carrier so I just have them snugly packed in right now.

Time to tear it apart and try again without the pinion shim :)
 

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Discussion Starter · #14 ·
Ok I took the pinion shim out and the markings look like the depth is good. The first time around looked like it needed less backlash so I moved some shims to the gear side.

This is where we stand now on the markings? What do the experts think?


There is virtually no remaining backlash now and the pinion has become considerably harder to turn (I have to use my breaker bar now -- before I could turn it by hand). Is this something to be concerned about?
 

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When the gears are set-up correctly you should be able to turn the pinion yoke by hand. If you need to use a breaker bar the gear contact is much too tight. Just out of curiosity, why are you sending us the concave pattern on the ring gear? This is the coast side and not the power side. I always take my pattern readings on the convexed side of the ring gear teeth. The pattern IMHO appears to have the pinion gear too deep into the rear axle housing. I know you said the shim was removed, try moving the ring gear slightly away from the pinion gear (this will give you backlash). This is a trial and error job as you are finding out, be patient and you will be successful.
Bill
 

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Discussion Starter · #16 ·
When the gears are set-up correctly you should be able to turn the pinion yoke by hand. If you need to use a breaker bar the gear contact is much too tight. Just out of curiosity, why are you sending us the concave pattern on the ring gear? This is the coast side and not the power side. I always take my pattern readings on the convexed side of the ring gear teeth. The pattern IMHO appears to have the pinion gear too deep into the rear axle housing. I know you said the shim was removed, try moving the ring gear slightly away from the pinion gear (this will give you backlash). This is a trial and error job as you are finding out, be patient and you will be successful.
Bill
I thought that the gear marking could be taken from either side. I have marking compound on both sides and can take a picture from the other angle tomorrow. I will also increase some backlash. It was set at .005 and the pattern from my understanding said decrease the amount. Thank you for the information.
 

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Discussion Starter · #17 ·
OK, I got it to .07 backlash and can turn the yoke by hand. However, now I am back to the markings that were reading to decrease backlash. I am quite stumped to say the least. Here are pictures of the marking compound on oth the drive and coast side of the gears.


Any comments or suggestions?
 

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What gears did you use ? If they have the pinion depth and backlash marked you would set the pinion depth correct and then the back lash. Then the pattern check is just to verify things. It is really hard to tell from your pictures. Summit sells a inexpensive pinion depth checking tool that will work in a pinch if you do not want buy the expensive one. Take your time and get it right or you will be doing it again Really soon. I also have the Richmond gear DVD that does help a bit.
 

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Based on what I am seeing on the gear teeth you need to reinstall the shim at the pinion gear. The pinion gear is contacting the ring gear at the outer diameter of the ring gear, this is unacceptable. The objective is to set the gears up so that the pinion gear contact to the ring gear is a nice smooth wipe along the center of the ring gear teeth on the gear power side. You were IMHO closer to the ideal when you first began the setup. As someone said previously a thousanth or two can make a world of difference in the setup. Remember, if you want to bring the pinion gear deeper into the ring gear add a thicker shim; to pull the pinion gear away from the ring gear install a thinner shim. I hope this helps.
Bill :yes:
 

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Discussion Starter · #20 ·
OK I put about 2/3 of what was originally shimmed on the pinion and reset the backlash to about .007.

Here are the markings, let me know what you think.

 
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