Need help with this pattern - pics inside
Thread Starter
Staging Lane
Joined: Jan 2006
Posts: 55
Likes: 0
From: Lakeland, FL
Need help with this pattern - pics inside Hey guys. I am in process of rebuilding the rearend in my 1999 Firebird. Need some advise here. Can you explain me what do I see here and what do I need to do to fix it if it is possible. Yeah I have two 0.031 pinion shims and backlash set at 0.010
Thanks
Thanks
Originally Posted by Firebird!
Hey guys. I am in process of rebuilding the rearend in my 1999 Firebird. Need some advise here. Can you explain me what do I see here and what do I need to do to fix it if it is possible. Yeah I have two 0.031 pinion shims and backlash set at 0.010
Thanks
Thanks
Do you have BOTH .031 shims in it now?
Thread Starter
Staging Lane
Joined: Jan 2006
Posts: 55
Likes: 0
From: Lakeland, FL
I am using gear marking campound mixed with gear oil. and sorry there is three pinion shims in there now. I tried 4 but the pinion sticks out too much and caches on the differential. 
can you get some gear marking compound? from what i can see, it looks like the differential need to move left a little and the pinion needs to come back more. we could say better though with gear marking compound. i would say take our opinions as a grain of salt until we tell you what we think after seeing the pattern in gear marking compound.
Here is a couple of tricks I use.
1. Use the diff/ring gear to turn the pinion when getting the pattern, not vice-versa. This tends to load the pinion much more than when you turn the pinion and try to hold the diff to displace the grease/compound. Also helps if you can put some drag on the pinion yoke with a rag or wrench or something.
2. Make big moves initially, so you can see where you are and which direction things are going. Looks like you are too deep right now, and you said you have 4 shims in it, so take out three of the shims and check the pattern, make sure it moves all the way to the tip of the tooth. That way you know 4 is too deep and 1 is to shallow, then you can start moving in from there.
Good luck !
1. Use the diff/ring gear to turn the pinion when getting the pattern, not vice-versa. This tends to load the pinion much more than when you turn the pinion and try to hold the diff to displace the grease/compound. Also helps if you can put some drag on the pinion yoke with a rag or wrench or something.
2. Make big moves initially, so you can see where you are and which direction things are going. Looks like you are too deep right now, and you said you have 4 shims in it, so take out three of the shims and check the pattern, make sure it moves all the way to the tip of the tooth. That way you know 4 is too deep and 1 is to shallow, then you can start moving in from there.
Good luck !
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With no shims you are definitely too shallow.
With 1 shim, you might be a little too deep still.
How thick are your shims, are they all the same thickness ? You might want to try a shim between those two.
With 1 shim, you might be a little too deep still.
How thick are your shims, are they all the same thickness ? You might want to try a shim between those two.
Looks pretty good to me the best I can tell depth-wise.
What is your backlash? The best I can tell by the pictures it looks like you need to loosen up a little on the backlash.
Not being ugly but the reason you have different thickness shims is so you can move it a little, I mean .002-.003 at a time to get it ideal. Get an assortment for the next one you do. You should never have to move a pinion anywhere close to the amount you were trying.
Stick with it, this is the best way to learn. Good Job.
What is your backlash? The best I can tell by the pictures it looks like you need to loosen up a little on the backlash.
Not being ugly but the reason you have different thickness shims is so you can move it a little, I mean .002-.003 at a time to get it ideal. Get an assortment for the next one you do. You should never have to move a pinion anywhere close to the amount you were trying.
Stick with it, this is the best way to learn. Good Job.
Thread Starter
Staging Lane
Joined: Jan 2006
Posts: 55
Likes: 0
From: Lakeland, FL
I got shim assortment from eBay, but all 4 pinion shims were 0.030-0.031 same as my original shim. But the guy who I got pinion/ring from included pinion shims too, they were about 0.012-0.015. So because I was really close with 0.031 shim than with no shims I decided to put two small shims with total of 0.025 than go less than half of 0.031 to stay closer to 0.031.
Anybody else guys? what do you think?
Anybody else guys? what do you think?
11 Second Club
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Joined: Sep 2002
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From: Albuquerque NM - The Land of 8000ft DA
I had the same delima as you.
I just ordered some more pinion shims, hopefully in smaller increments, because my gear pattern looked similar to yours.
I think the drive side looks fine but not convinced on the coast side. I'm not an expert by any means either.
Hopefully someone with more experience will chime in.
I just ordered some more pinion shims, hopefully in smaller increments, because my gear pattern looked similar to yours.
I think the drive side looks fine but not convinced on the coast side. I'm not an expert by any means either.
Hopefully someone with more experience will chime in.
I think you are very close, probably good for best strength, but might be a little noisy that deep. If you wanted to be a perfectionist and go for a quieter setup you might want to try an .022 or an .020 shim.
What lash are you checking it at ?
What lash are you checking it at ?
Oh, sometimes the shim packs have a variety of shims, like .011, .013, .014, .015, and you have to mix and match to get the desired depth.
But yeah, even the Ratech shim kits are pretty chincy with the shims.
But yeah, even the Ratech shim kits are pretty chincy with the shims.