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09-04-2018 #1Registered User
- Join Date
- May 2008
- Posts
- 20
THE quietest ring & pinion - US Gear with "Lightning" treatment, or ?
Search isn't finding "US Gear" instances, so posting this question. For GM 12 bolt 8.875" car design running between 3.90 and 4.30 gearing, what vendor has proven to be the quietest?
I'm open to ideas, as we're fighting a battle on our 40K mile 1-owner Z/28's 12 bolt which came with 3.73s. Since 2004, we've had 4.10 (40 tooth ring, 10 tooth pinion) gears from Reider thick 4.10s(2004-18), Yukon regular 4.10s (Aug 2018) and Motive thick 4.10s (Sep 2018) in our 12 bolt, including 3 and 4 series carriers, and still have either a loud howl (Reider & Yukon) or light whine (Motive).
Per USG's literature, they do all their manufacturing in Chicago, IL and perform a special treatment that polishes the gearset - currently used in Indy, NASCAR & trophy trucks. So that coating might be worth the extra $100 vs. non-coated.
Next question comes to tooth count. Some theorize that having more teeth meshed at any given time improves strength, and some say it also reduces risk of noise since more teeth are meshed at any given time. That would lead me to conclude that my best option would be US Gear's 3.91:1 ratio with 11 pinion / 43 ring teeth, followed by US Gear's 4.30 ratio with 10 pinion / 43 teeth. At that point, I'm concerned US Gear's 4.11 setup uses 9 pinion teeth and 37 ring teeth (vs. Motive, Yukon, etc. doing 4.10s via 10 pinion / 41 ring teeth).
Goal is to get this thing back to nearly noiseless. Our local highly-reputable shop with 20+ years of experience specializing in diffs, is pulling their hair out after 3 different gearsets being noisy. Our Reider"thick" 4.10 set was meh in 2004 and progressed to the outrageous howl by 2018 that you hear in the bottom link below, shot with camera zip tied to tank (which is about as loud as the interior was FWIW). So we tried Yukons on a proper new 4.10 carrier, thinking that thick gears might be contributing to the noise - but these were no better. We tried Motive thick 4.10s on a 3 series carrier after that - those have been the quietest so far (but nowhere near as silent as the original 3.73s). Kicking myself for changing out the original 3.73s back in '04 but I had no idea how hard it would be to find semi-quiet gears & just wanted 4.10s to optimize my 1/4 mile powerband (high 11s, 121 MPH on drag radials running 6400 RPM thru traps - right at 6500 RPM power peak, 3600 RPM soft launch 1.78 60 ft), autocross, early morning twisty road drives.
Thanks for whatever experiences you can share with various vendors & setups.
Yukon 4.10s:
Motive 4.10s:
Reider 4.10s:
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09-04-2018 #2Registered User
- Join Date
- Aug 2004
- Location
- Texas
- Posts
- 326