Road racing differential
Thread Starter
Advanced
Joined: Jun 2015
Posts: 92
Likes: 2
From: San Jose CA
Road racing differential
I have a coupe street/track car with some power mods, coilovers, bbk, etc.
I was noticing my diff getting weak and after changing the fluid, i tried to measure its preload and it has none. It is virtually an open diff. It whines too.
my question is:
1. If i rebuild it with c6z parts, will i be able to adjust the meshing to get rid of the noise? It's loud on accel, silent on decel so i assume it's the ring and pinion. I've done it on normal diffs but i know these are different.
2. If i decide to go with an OS G or a quaife, will i be able to adjust it to fix the noise?
3. Any feedback on either diff option is appreciated. I have tons of track experience with helical diffs (rx7, miata, s2k) and prefer clutch types personally.
I was noticing my diff getting weak and after changing the fluid, i tried to measure its preload and it has none. It is virtually an open diff. It whines too.
my question is:
1. If i rebuild it with c6z parts, will i be able to adjust the meshing to get rid of the noise? It's loud on accel, silent on decel so i assume it's the ring and pinion. I've done it on normal diffs but i know these are different.
2. If i decide to go with an OS G or a quaife, will i be able to adjust it to fix the noise?
3. Any feedback on either diff option is appreciated. I have tons of track experience with helical diffs (rx7, miata, s2k) and prefer clutch types personally.
Team Owner
Joined: Oct 1999
Posts: 31,976
Likes: 487
From: Guinness Its whats for B'fast JAWGA
CI 3-4-5-9 Veteran
You may get better results in the autocross / road race section. I maybe in the same boat soon with a diff that is whining.
https://www.corvetteforum.com/forums...stock-lsd.html
https://www.corvetteforum.com/forums...stock-lsd.html
Last edited by 93Polo; Jan 10, 2020 at 10:44 AM.
Drifting
Joined: Mar 2015
Posts: 1,421
Likes: 302
From: CSRA, SC
You need new everything. Your ring/pinion are permanently damaged and pieces of metal floating around in your diff have probably damaged most everything else because your preloading belville washers are snapped. I have to replace my diff a second time very soon as well because I was foolish and put another OEM diff in it from a junkyard car. This time I'll be putting RPM in it and forgetting about it but that may or may not be the best option for YOU. My rebuilder told me the diff carrier was damaged in mine but I don't know what happened to it exactly.
Burning Brakes
Joined: Apr 2004
Posts: 786
Likes: 46
From: Tucson, AZ
Just a note on my situation. I purchased my car with a fairly loud whining diff on throttle... off throttle no noise. 65 track days later still whining the same.
For preload I started out around 100-ish, then gradually to zero preload... been at zero for awhile now but corner exit I still have an LSD. Decel prob different story but not as easy to assess for me.
So my conclusion, everything's OK despite noise and no preload... I will rebuild it just not in a super hurry, waiting for clutch to go.
For preload I started out around 100-ish, then gradually to zero preload... been at zero for awhile now but corner exit I still have an LSD. Decel prob different story but not as easy to assess for me.
So my conclusion, everything's OK despite noise and no preload... I will rebuild it just not in a super hurry, waiting for clutch to go.
Thread Starter
Advanced
Joined: Jun 2015
Posts: 92
Likes: 2
From: San Jose CA
thanks for the feedback guys.
So i'm concluding that my current diff is not worth fixing. Better get a fresh used one and decide what to do with that.
My car definitely has a hard time putting power down, less so on track since i'm never in first and hardly ever in second but still.
i'll probably get a stock one and fit it with new bellvilles and used that for now.
So i'm concluding that my current diff is not worth fixing. Better get a fresh used one and decide what to do with that.
My car definitely has a hard time putting power down, less so on track since i'm never in first and hardly ever in second but still.
i'll probably get a stock one and fit it with new bellvilles and used that for now.
Melting Slicks
Joined: Nov 2017
Posts: 2,306
Likes: 747
Call Jerry at Unitrax in Anaheim unless you plan on doing it all yourself. They did shot peened and polished 4.10s in mine with the diff still on the car. Cheaper than everyone else I checked with, great reputation, and not a single issue or noise/whine 
Drifting
Joined: Sep 2009
Posts: 1,862
Likes: 594
From: Prescott, Arizona
My car is an A4, RPM 3.73 rear drive with WAVETRAC differential. I like it, use only 2nd and 3rd at Laguna Seca.
http://www.wavetrac.net/
Your bellville springs are probably broken, but the spider gears still load the clutch packs without them, just not as much. A buddy of 60 years who raced C2's mentioned that he raced without the clutch pack springs. Even so, if your clutch packs are worn, your rear drive may act like an open differential.
http://www.wavetrac.net/
Your bellville springs are probably broken, but the spider gears still load the clutch packs without them, just not as much. A buddy of 60 years who raced C2's mentioned that he raced without the clutch pack springs. Even so, if your clutch packs are worn, your rear drive may act like an open differential.
Thread Starter
Advanced
Joined: Jun 2015
Posts: 92
Likes: 2
From: San Jose CA
My car is an A4, RPM 3.73 rear drive with WAVETRAC differential. I like it, use only 2nd and 3rd at Laguna Seca.
http://www.wavetrac.net/
Your bellville springs are probably broken, but the spider gears still load the clutch packs without them, just not as much. A buddy of 60 years who raced C2's mentioned that he raced without the clutch pack springs. Even so, if your clutch packs are worn, your rear drive may act like an open differential.
http://www.wavetrac.net/
Your bellville springs are probably broken, but the spider gears still load the clutch packs without them, just not as much. A buddy of 60 years who raced C2's mentioned that he raced without the clutch pack springs. Even so, if your clutch packs are worn, your rear drive may act like an open differential.
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Drifting
Joined: Sep 2009
Posts: 1,862
Likes: 594
From: Prescott, Arizona