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Corporate 10 bolt gear change

pierce88K5

pierce88K5

1/2 ton status
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Jan 11, 2005
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Location
Alexandria, VA
I have an 88 K5 Blazer that has the factory posi-track corporate 10 bolt rear end with 3.73 gears. I recently changed out the ring and pinion shaft to a 4.11 gear set. I set up the pinion shaft and discovered that the pinion shims that came out with the old 3.73 gears were between the inner pinion bearing and the crush sleeve. It looks like they were installed incorrectly because they appear to not touch anything and are just loose on the pinion shaft. Can anyone tell me where to shim the pinion?
Thanks.
 
Pinion shims are supposed to go between the head of the pinion and the lower pinion bearing (basically, under the lower pinion bearing).

Its easiest if you use a setup bearing for this since you would otherwise need to press the lower pinion bearing on and off every time you had to change shims. A setup bearing is one that is simply ~.005" larger in ID such that it will slide on and off the pinion without a press, I've always ground out the ID of a used or new bearing for this.
 
Chris,
I thought the shims were in the wrong place. When I had the old inner bearing removed, there was a shim there that replaced and thought I had to shim the pinion depth forward of that. But, it looks like I am going to have to shim the pinion under the inner pinion bearing. I ran a check on the gears without the shims and I am having some difficulty in reading the pattern. Do you know how to post pics on this forum?
Wes
 
pierce88K5 said:
Chris,
I thought the shims were in the wrong place. When I had the old inner bearing removed, there was a shim there that replaced and thought I had to shim the pinion depth forward of that. But, it looks like I am going to have to shim the pinion under the inner pinion bearing. I ran a check on the gears without the shims and I am having some difficulty in reading the pattern. Do you know how to post pics on this forum?
Wes
Click to expand...

Make an account on photobucket.com (its free), upload your photos there and then copy the url and post it here.

You would normally be able to use the IMG code from there to make your pictures show up here but there's a new rule here that you can't link images until you get to 20 posts or something, to prevent spam I guess.
 
Chris,
My wife just uploaded the pics to her photobucket account and then I found out that I had to make 15 posts before I could link a post to it. The pattern looks a little to the heel side. I will probably just show the pics to a friend of mine at church that builds race cars and see what he says. I appreciate your help.
 
Just give us the link to your photobucket account or to the individual pictures.

I've setup a couple dozen diffs, there are plenty of other people on here with diff experience too.
 
Chris,
Here is the link. Just type in http// in front of it to make it work:
s274.photobucket.com/albums/jj248/wesjoy70/?action=view&current=IMG_5926.jpg
Let me know what you think.
Wes
 
Not quite deep enough, ~.003" deeper and you'll be there:

IMG_5926.jpg
 
Chris,
Thanks. I knew it didn't look quite right. I will get back to you after I shim it on Monday or Tuesday.
Wes
 
Chris,
I had some time today to mess with my pinon on the corporate 10 bolt. I had to cut off the new bearing (it's amazing what you can do with a dremmel tool and a whole lot of patience!). I bought two new bearings and made one a set up bearing. I put the old .034" shim back in with a .012" shim and this is what I came up with:
i274.photobucket.com/albums/jj248/wesjoy70/IMG_5927.jpg
Let me know if I am on the right path or not.
Thanks,
Wes
 
Pretty tough pattern to read, are you putting pressure on the ring gear while you spin the pinion? Also, try thinning the paint a little with some gear oil and take another pattern.
 
Chris,
I am spinning the ring gear with my hand. I am guessing that I need to turn it with the pinion instead? I will go and test it again with thinner paint and post the pics shortly.
Thanks,
Wes
 
Chris,
The more I look at the pattern, the more I think it is too far in. In your first post, you thought I needed to go about .003". Right now with the stock .034" and the .012" shim (which is the smallest shim in the kit) that puts me at .046". I will probably rearrange my shims and get it down to .037" and try that. Since it is getting late here in SC, it will have to wait until tomorrow. Hope to catch you then.
Wes
 
Chris,
I tried the .037" shim and it was still too far in and then I tried .042" and this is what it looks like:
i274.photobucket.com/albums/jj248/wesjoy70/IMG_5934.jpg
Looks to me like it is centered. Let me know.
Thanks,
Wes
 
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