Gear Pattern.... yay or nay??
- Thread starter Bullett801
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LOL, no I have not. that is why I am asking so many questions. Sorry about the lack of knowledge..... But I will get it. Im patient and know my way around a car pretty well. But thanks for the offer 500/600. I am good though, I am pretty sure I have all the parts to get the job done. I will try no to ask so many questions.
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You need to put the original pinion shim back in. If your backlash is off you will need to shim the carrier differently. Sometimes it is as simple as swapping shims side to side. Sometimes that makes it worse. You do not adjust backlash by changing pinion shims. Even though it does effect backlash is has much more effect on pattern. Thus my offer to send you the right shims once you know what they are. Or better yet buy adjustable shims and play until you get it correct. You’d be better off with a little too much backlash than the wrong pinion depth.
Put the stock pinion shim back in and start over.
This is looking like a good place to use a real pinion depth setting tool. It mounts into the carrier bearing caps and measures the distance to the face of the pinion gear. I have done quite a few and always found that once measured the needed pinion shim was within one or two thousandths of what the factory had for the used pinion gear I was installing. I quoted this from an email Bill sent to me- " I am using all new bearings, a used set of gears, (3:73) and a used but checked and verified Auburn 28 spline posi. I used the pinion shim from the gear set that I got, (OE pinion shim from the rear differential was .038 and the one with the gears was .034, hence the first question) and set pinion depth and pinion bearing preload to 12-15 in lbs. " Since neither shim is getting the tooth pattern I would use a depth setting tool to see what is going on.
There is not a good way of using a pinion depth tool on stock gears because they typically do not have a check distance engraved on them to go by.
About all you can do is use that stock shim. Get the backlash right. Run a pattern with the correct marking compound. Adjust pinion depth AND backlash until you get an acceptable pattern.
I believe that if the OP puts the stock pinion shim back in and gets the backlash anywhere between 0.006” and 0.015” he will be good to go.
Why worry about 0.002”-0.003” when we don’t even have tools that measure that repeatable. This is not crankshaft bearings.
A friend of mine who did rear ends in his sleep always started with .030 shim on the pinion with new gears and that worked, according to him, about 99% of the time. He would charge guys on side jobs $100 to set up a rear end
Different rears had different ‘go to’ pinion shims thicknesses, but your friend is exactly right. I have so many pinion and carrier shims from hundreds of setups that the only way to tell them apart is ID and OD measurements. And a good gear ‘setter upper’ can get backlash within 0.001”-0.002” just by feel with their eyes closed.......literally.
And I agree 100%. It just came to me that the OP might be using the pinion shim to adjust backlash. No no no no no. Personally I’m glad he asked because we all want it to go right for him. And just because you have never done it doesn’t mean don’t do it. Ask away.
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