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Absolutely. I am on detachment for the next few weeks but I can definitely ship the R and P when I get home. The LSD carrier has part numbers on it so good news...that is probably a part that shows up in high performance cars. If any of you sleuths want to search for it, it is part number 64_0025_01. The underscores are missing numbers that were drilled through for the assembly. My best guess is that the first number is a 6 or 8 or 0. The second missing number is possibly a three? If we can id the carrier we might have better luck figuring out what the ring gear is. I’m still planning on buying a Chrysler set from amazon and checking the specs and then sending it back if it doesn’t make sense.

I drilled an access hole in the top of the diff so I could measure backlash. After replacing only the carrier bearings on my second diff and the noise getting worse, backlash plays a huge role in the noise of this gear set. I bought a new shim set that I think will work for the carrier but unfortunately I’ll have to weld the races out again and buy two new sets of carrier bearings. One set of races I have to grind down to become the set up sets and the others would be the final install. So if this rebuild ever becomes an option two sets of carrier bearings would need to be bought.

Not sure if I’m super stoked to pull the diff again on a test run unless I’m completely sure the mesh is perfect. Although I’ve gotten pretty quick on the diff swap and gotten it down to 4 hours on jack stands in my garage. Keep the faith brothers, there is a solution...hopefully it’s cheap!
Awesome! You are a gentleman and a scholar.
 
Bad news guys. The Chrysler 8.7 IRS is not a match. The pinion is so damn close to being a match, pretty much the same thing besides the shaft diameter. The ring gear though is way off. The ring gear bolt diameter is smaller on the Chrysler and the overall face of the teeth on the Chrysler is much larger. The only chance of this set working would be if by some amazing chance of luck the LSD of the Chrysler had the same width as the Cadillac. Next option is the camaro SS rear ends. I already know the pinion spline count does not match and a different pinion yoke would have to be used which would mean custom driveshafts and $$$.

Looks like there may be no cheap way to replace the ring and pinion. IMO The wearing of the ring and pinion is what causes the gear noise. Unless the ring and pinion are replaced it will continue to whine. And why is it whining in the first place. I think the sandwich design of the differential is a root cause. The differential gets hit, the carrier and ring gears expand too much. Contact pattern is lost, gears are worn down and need replacement. However no gears exist which means no matter how great you are at setting backlash and making a good mesh it will whine unless it gets a new set of gears. And this will only happen again unless the differential gets a cooler.

So only real solution I see is one of these gear companies see that there is a dime they can make off of the V and diff coolers get cheaper and easier.
 
Damn, bummer. Thanks for all the effort, though.

Based on other issues I've heard of, it sounds like the bearings are just as prone to fail due to heat...but you don't think they contribute to whine? If it looks like a cooler will save them, then that puts a fire under my ass to do one this winter, hah.
 
I went through two diffs under warranty. I put the cooler on immediately after doing the break in on the third diff. My pump is on a 180* thermostat and on an 80* F day driving for ~30 minutes at ~75-80 MPH the pump will kick on. These things run hot. I encourage everyone to put a cooler on whether you are tracking or not. You're not going to see the over temp message without tracking it but that over temp message is ridiculously high. Just because you don't see the message doesn't mean the diff isn't getting hot.
 
I went through two diffs under warranty. I put the cooler on immediately after doing the break in on the third diff. My pump is on a 180* thermostat and on an 80* F day driving for ~30 minutes at ~75-80 MPH the pump will kick on. These things run hot. I encourage everyone to put a cooler on whether you are tracking or not. You're not going to see the over temp message without tracking it but that over temp message is ridiculously high. Just because you don't see the message doesn't mean the diff isn't getting hot.
Are you referring to the original factory cooler or an aftermarket one?
Suppliers?
 
I made my own and will gladly offer my learnings to anyone looking to do the same and avoid my mistakes. I don't know what the thermostat temp is on the GM cooler but it does have one. I'm not sure how the Weapon X or D3 coolers do the thermostat or what the pump on temps are on their thermostats. The revision of the GM cooler so that it would fit the coupes is available. I think username AC Promotions on here can get you hooked up if you contact him. I have someone's contact info to get the GM one too. It is pricey though.
 
I emailed US Gear to see if they had any appetite for making a set of gears. Below is their reply

Thank you for your inquiry- I have a friend that had a CTS-V, he mentioned this before to me. We can cut and heat treat just about any gear, it just boils down to a math problem of determining how to cover the tooling and minimum run quantity for our plant in Chicago. We have seen a number of enthusiasts convert their rear axles from the stock or OE design over to a Ford 9” (or something similar) to resolve issues with being able to handle the power or other issues. Example- The IRS Camaro SS 8.6” rear axle, we tooled the application up and have not moved many gears at all since 2010. We’ve found that most are converting to a Ford 9” solution (even the Copo Camaro has a Ford 9” from GM- we know because we make the gear-set for it).

Typically to break even (depending on sell price) we need to sell roughly 500-750 ring & pinions after paying for tooling. How large would you say the market potential is? Do you know if GM completely discontinued the ring & pinions or are they behind on supply? What would be the target retail price most would be willing to spend?

Thanks in advance and we appreciate you reaching out!


So it looks like they would be willing to make gears if they had enough interest. I don't think that there are 500-750 V owners out there willing to dive into their differential. Plus, who knows if GM is going to make a fix or start producing these units again.
 
I emailed US Gear to see if they had any appetite for making a set of gears. Below is their reply

Thank you for your inquiry- I have a friend that had a CTS-V, he mentioned this before to me. We can cut and heat treat just about any gear, it just boils down to a math problem of determining how to cover the tooling and minimum run quantity for our plant in Chicago. We have seen a number of enthusiasts convert their rear axles from the stock or OE design over to a Ford 9” (or something similar) to resolve issues with being able to handle the power or other issues. Example- The IRS Camaro SS 8.6” rear axle, we tooled the application up and have not moved many gears at all since 2010. We’ve found that most are converting to a Ford 9” solution (even the Copo Camaro has a Ford 9” from GM- we know because we make the gear-set for it).

Typically to break even (depending on sell price) we need to sell roughly 500-750 ring & pinions after paying for tooling. How large would you say the market potential is? Do you know if GM completely discontinued the ring & pinions or are they behind on supply? What would be the target retail price most would be willing to spend?

Thanks in advance and we appreciate you reaching out!


So it looks like they would be willing to make gears if they had enough interest. I don't think that there are 500-750 V owners out there willing to dive into their differential. Plus, who knows if GM is going to make a fix or start producing these units again.
500+ seems like a lot for the V community. Did GM really stop making the ring and pinion? Or you just can't buy them alone?
 
Yeah you'd be lucky to get 10 people to sign up, bah. Maybe I should still hold onto my Ford 8.8 and have something made for it...
 
Keep in mind the Gen 5 ZL1’s use identical rear diff, probably still won’t hit the 500 target.




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Keep in mind the Gen 5 ZL1’s use identical rear diff, probably still won’t hit the 500 target.




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First search shows me that only 14,000 5th gens were made...there were 20,000 Vs, and 5th gen owners are probably even cheaper bastards.
 
I think the ring and pinion are the same 9.9 size.

I see from your pictures the mounting is way different.


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That thing looks way too dinky to be behind an LSA...
 
I still am flabbergasted that the CTS V differential is apparently a one-off piece? Surely there is cross-over somewhere.
 
That thing looks way too dinky to be behind an LSA...
Ford 8.8 isn't any bigger and can take twice the beating (shrug)

I still am flabbergasted that the CTS V differential is apparently a one-off piece? Surely there is cross-over somewhere.
Yes, and walkers has vigorously researched with no major progress, haha. Everyone just get a damn diff cooler, stat!
 
The Gen5 ZL1 diff was nick-named "The Beast" in articles I read. It weights 144lbs, has a built in cooler in the bottom of the case (trans fluid circulates back to the cooler brick to lower temps by 100degrees, etc) and was just totally overbuilt by GM - for a change. I wish the CTS-V had that diff in it. I never read about any ZL1 having any issue with the rear, like we have. It is supposed to be damn near unbreakable.

Unless I am going crazy (probably) I swear the price of the ZL1 diff was $1999 with axles to bolt into your SS camaro, etc...now the price is $4700 - so GM doubled it in the past year, WTF?!?!

https://www.chevrolet.com/performance/gen5camaro/powertrain
 
I think all the 5th gen Camaros had AAM diffs but i could be wrong. I don't think the ZL1 and V used the same diff.

I'm not so surprised that the V is the only GM with the diff but I can't believe Getrag supplied GM and Chrysler with such similar gears that are different. You would think the internals would have been the same with just interface differences in the cases and the flange for the prop.
 
The ZL1 internals are different than the V. The pinion has a different main shaft diameter and is 32 spline vice 30. It also uses the new style pinion flange with the three bolts vice our cup design. I don't think there is any cheap options out there to finally fix the problem. If you can get your hands on a super hard to find now new differential, slap it in and get a cooler on it. Used units are not worth the risk as you cannot tell if it will whine until it is on the vehicle and under load.
 
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