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Hi, i have a question about getting this gear pattern right. Its for a 2:86 ratio out of an 82 vette dana 44. Heres my problem. With any amount of pinion depth i add or take away, the pattern really doesnt seem to change, it looks like it needs the pinion further in. I am at 48 thousandths right now and i have been as high as 55. What do you guys think i should try?
Looks like you need more backlash to get a readable pattern. Go back to the pinion shim it had originally, and set backlash and then take a pattern.
I started at 45 thousandth's under the inner pinion race, thats what Tom's differentials suggested. So then I started playing around but nothing seems to change on the coast side, the drive pattern will go to the middle but not the coast, it stays in the toe. It had 42 thousandth's when we took it apart, but since the rear ends been apart before I don't know if thats correct, but I've tried starting at that. I usually set the backlash at 7 and a half. Do you think the ring and pinion could be worn out? The rear end only has 40 thousand miles on it, but it needed clutches and everything because of metal and clutch keepers flying around in it. it also needed the case replaced due to a crack.
I'm no expert, but used gears should have a contact patch pretty much across the whole tooth. I'd try opening the backlash to 0.010. Then wipe off all the marking compound before doing another pattern. Also, are you giving the side yokes a good spin? You need some force on the gears to get a good pattern.
Gears are used up when the pattern goes all the way to the outer edge and you can see metal rolled over the edge on the drive side.
When setting a gear pattern, there needs to be some loading placed on the output...not just a 'free' run pattern. You can do that manually by resisting motion on one gear while turning the other. That will help spread the pattern a bit and make it clearer to see.
When the gear is actually working in the car, the actual contact area will be shifted more to the center of the gear due to increased loading, so the pattern you want to see when setting it up is a lightly-loaded pattern which is off-center a bit. But it still should be about 1/2 way up the tooth face (not toward tip or root).
Last edited by 7T1vette; Aug 11, 2016 at 10:06 AM.
Question about gear patterns
