My old 7.5 started making clunk clunk noises on sharp right turns. So I headed out to pick-n-pull and found a 96 vert with a traction loc 3:08 and $100 and some sweat later I headed home. Pulling it apart I pulled the too long 5 lug axles so that I could use my 4 lug axles from the 7.5 (I just mounted some nice 4 lug wheels and new 275/40/17 tires). I ordered new clutches and a ring & pinion install set along with motorsport 3:73 gears for it. I saw some of the ears were broken off a few clutch friction discs and some scraping on the inside of the diff cover! The horrah! Pulled out the carrier and popped off the ring gear, installed new clutch hardware (modified stack), and wiped off the pinion to pull it out. That's when I noticed it was a motorsport 4:10 set. When I pulled it out I found some of the clutch disc ears underneath it. Someone did something nasty to the original gear set I suspect. Anyhow I cleaned it all out and decided to go with the 3:73's but decided whomever installed the 4:10's likely didn't do it right (although they look perfectly fine).
So now I'm starting from an unknown pinion shim thickness and began with .032" but it had a pattern on the driven side way out on the heel (outboard) side after setting .010" free play. I read since then the pinion depth should be 4.420" from the center of the ring gear but I didn't try to measure that before I began. Anyhow playing around and adding more shim to the pinion is moving the rub pattern inboard on the driven side. The coast side is rubbing on the toe (inboard end) of the ring gear teeth and adding more pinion shim thickness is helping it move towards the gear tooth center. I'm now up to .074" of pinion shim and have lost some of my free play which needs to be re-shimmed on the carrier bearings. This should also change the wear pattern somewhat from what I've read correct? Is .074" too much shim?
Note: This is my first try at this although I understand the basics of to set up gears and bearings etc. I did torque the pinion and bearing caps to assure everything is where it should be (no pinion crush ring just yet though) and used a cheapo bearing dremel-relieved for a slip fit on the pinion for setting it all up.
I am going to use a known thickness flat bar and depth mics to get a pinion depth measurement noting the bearing cap mount surface may not be at the center of the ring gear (I'll check for that and do the math to correct for it) just to do a sanity check at this point.
Advice from those with experience is appreciated. They've actually figured it out already!
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