Yukon Gears

[compuwiz1937]

I am looking at building a 218mm Camaro differential for my SS Sedan with 3.73 gears. As far as I can tell, whatever the company that used to make a 3.70 gear for the Camaro differential that everyone said was good is no more (or at least the product is), and Yukon is the only company that makes something close, which is the 3.73. I searched around here and didn't find a whole lot, but the posts I found just said they were noisy but no more information than that. What kind of noise are we talking about? A steady gear whine, warble, or something else? Are there any vibration issues that come with the noise? That is my biggest issue because I replaced my stock differential with the Camaro differential because of the rumbling noise and vibration that could be felt on the highway that was incredibly annoying. I feel like I can deal with some noise as long as there is no vibration. I've tried the 3.91 and the 3.45 ratios so far and they just aren't a good match for the transmission ratios in the SS sedan, unfortunately. The Yukon gears are on Black Friday sale now so I'm thinking about doing it. Unless someone has some other suggestion? The ZL1 differential does not fit in the SS sedan subframe without modification, so that isn't an option.

[ss camaro-monte]

I have them in my diff with a Detroit locker. They are louder than stock but honestly I don't really notice it. I have cam, stall, heads and back seat delete and poly bushings.polyurethane bushings make more noise than anything over bumps.

I went with the 3.73s because 3.91 was a little more gear than I wanted on the highway and I can tell you it is a lot of gear for the 6l80e still with my 3200 stall, built suspension and nitto drag radials. I still can't hook until deep into 2nd on the street and i am at 460rwhp. Will be getting some new shocks and more rear suspension mods and moving to Mickey Thompsons.

How much power are you making? Another option is the 3.45 with a smaller wheel. 18s or 19s. That would make up for some of the loss. But they do make more noise then the factory aam gears. No wobble or anything. I do recommend if you get a Detroit locker to use a good mineral based oil like motul sae 80w90. I had a lot of noise in my locker after gpi did my gears and when I switched to what eaton recommended it all went away. Would have popping noises when I turned sharp turns and when I switched to the motul 80w90 mineral based it all went away.

Do you have anything done to your car yet?

[ss camaro-monte]

Also if you had factory aam 3.45 or 3.91s and heard noises something wasn't set up right is my guess. The 3.70s you were referring to were made for lingenfelter by aam.

If you are a stick car 3.91s are not to much gear for the 6 speed stick. A lot of guys run 3.91 in all NA motors and GPI even recommended them when I did my gear swap but I am glad I didn't. 3.73 vs 3.91 isn't much if any performance gain and if I can't hook on 3.73s 3.91s would be even harder with the 6l80e.

I also got 3.73s because I thought if I ever do go supercharger I could probably live with that gear if I could actually get traction. But I already have the rear built 80% and I am having traction problems at my power level.

When I just had fbo stall and rear suspension I could hook on nitto drag radials. Now that I added a 100 rwhp it is a no go.lol
Went from a 12.2 to a 11.58 and my 60ft went from a 1.6 to a 1.74 even though I am making more power and have more gear.
But the 40 rolls are hilarious. Lol

[CamaroCracka]

I have Yukon gears and a Yukon locker in my truck, and they worked great, but I would never be able to hear a little gear noise over the tire noise so I can't say how quiet they are. Yukon does have a good reputation in the off-road world.

From what I have read, Yukon and other gears can be louder because of the material used and how they are cut (2 vs 5). The factory AAM gears are known to be the quietest, so any other gear will likely be louder. I would give Yukon a call or email their tech department.

Given the price of ZL1 diffs these days, they are almost not worth it given the limited gear selection. For a bit more you can go 9 inch or S60 and have something nearly unbreakable with a much wider choice of ratios and solid aftermarket support well into the future. I actually have a spare gear set and master kit on the shelf because I am afraid I won't be able to find parts in 10 years. I've never heard of a ZL1 diff breaking, but I have personally snapped an axle, and I am only at 800ish.

[compuwiz1937]

My car is supercharged and cammed, solid rear cradle bushings, BMR toe and trailing arms. It isn't a race car, it has never been to the track and who knows if it'll ever go. I did not do poly bushings in the Camaro differential because I didn't want the noise. I'm sure the solid cradle bushings were why I had the vibration issue with my stock differential because I don't think there was anything wrong with the differential. I replaced it with a new stock differential first and had no change, then I replaced a ton of other parts trying to hunt it down with no change. I finally had access to another manual car (which was bone stock) and ran it up to the same speed on a lift and you could hear and feel it (being under the car, you can't hear/feel it inside in a stock car) just the same as my car. That's when I went with the Camaro differential, which fixed my issue. The 3.91 was very aggressive and the engine speed was too high on the highway and made it annoying. The 3.45 is much better in those regards but I feel like the engine is working too hard, I can feel it and I'm also still getting 10mpg like I was with the 3.91. The stock differential is 3.70, so it seems clear to me that ratio matches best with the transmission ratios, which I am not interested in changing. I'm not sure if I want to do the TruTrac, I mainly didn't want to do it for possible NVH reasons. Which is why I bought the lowest mileage Camaro differential I could find so the clutch LSD was in good shape. Either way, I'm not seeing anywhere with a Black Friday deal on a TruTrac, so I'm just going to buy the gears and sit on them for a few months more than likely. I'll probably end up buying another used Camaro differential so I can build it at my leisure and just swap it in when complete.

[ss camaro-monte]

Cheapest I could find was GPI for 759 for the true trac on black Friday but this is usually the cheapest time of the year to buy parts. Many parts suppliers have a 10-15?% off for black Friday.
Good luck.

[2012 Camaro SS]

In case you're still looking for a good price on the Detroit Trutrac differential, I bought my Detroit Trutrac from Weir Racing -- price is still what I got it at, $723, here is link:
https://weirracing.com/EATON-912A686/

I also went with the Yukon 3.73 rear gear, bought from www.cspracing.com.

I have some more road noise, but not too much, and I attribute to having also replaced all the suspension bushings, with BMR, using, in particular, for the rear cradle and differential mount bushings BMR part # BK030 - Rear Cradle Bushing Kit, Pro Version (BK024, BK029), which are made from 95-durometer polyurethane. I basically had installed every suspension upgrade BMR sells (all bushings, sway bars, tower brace, toe rods, trailing arms, lower control arms, sub-frame connectors, koni struts and 1" lowering springs), just did everything at once.

I replaced the diff cover with the Speedmaster cover.

I bought all the parts over a year ago but just finally got it installed, I only have maybe 5k miles driving on them at this point. So not a lot of miles yet to provide meaningful review, but so far enjoying it. I can report back after more miles if you are still deciding on the differential or gears, to advise if I've had any issues.

[compuwiz1937]

I’m still not getting email notifications from here any more. Thanks for the recommendation on where to buy the TruTrac. Does he stock them? What was the lead time? I bought the Yukon gears on black Friday and I picked up a 40k mile 3.27 Camaro diff, so I just need the TruTrac and bearings/seals at this point. I also bought Super Pro differential bushings on Black Friday but I’m very nervous about using them. I haven’t decided yet.

[2012 Camaro SS]

Weir Racing doesn't stock the trutrac differential. They cater more to Ford Mustang market, but they'll happily source and sell this part to you. It takes 2 - 3 days from ordering for the diff to get to them, and then they beef up outer packaging and send UPS on to you. I'd say on safe side give a couple weeks for total fulfillment of order. I had had to reach out to them when I first ordered because I put the wrong credit card info, and the message I got back was from the owner himself, Jordan Weir, who was super easy and good to work with.

As for whether or not to install the bushings, looks like the Super Pro are polyurethane, and from the research I've done, the increase in road noise is more noticeable / worse when you switch to bushings made from Delrin which are even harder than the polyurethane. The BMR bushings I had installed are also polyurethane and there is some additional noise, but there is no vibration, which your post indicated was a concern. If you're okay with some additional noise, I'd go ahead and install the Super Pro bushings you got when you put in the new differential since you'll have access at that time to do it.

The 3.27 differential you picked up, I believe for the 5th gen camaro, 3.27 differential came stock in the automatic and manual v6, and the automatic SS (v8). I'm not the knowledgeable on the subject, but this thread indicates depending on what engine (v6 or v8) and transmission (manual or auto) you currently have, the gear and rear diff swap may require more or less parts (but as noted, I don't really know what I'm talking about): https://www.camaro5.com/forums/showthread.php?t=591995

For the bearings/seals, since I bought the Yukon 3.73 gear, I bought Yukon's bearing/seals package too, they had two options, a more limited version, and a more complete version, so I went with the more complete option, product was called the Yukon Master Overhaul kit for '10 & up Camaro with V8, part number: YK GM8.6IRS. Here is a link to the product on Yukon's website, as you'll see, it's not cheap at $614.89: https://www.yukongear.com/shop/yk-gm...jiQTrVzhA8mwi6

You can buy it directly from Yukon at the link above, but for whatever reason, I sourced the Yukon master overhaul kit and 3.73 rear end gear from www.cspracing.com, and as I recall, it took a little while for CSP to source from Yukon. I don't think it was crazy long but I did reach out to CSP to see about the order and they had to reach out to Yukon and get back to me, but when they got back to me, they were able to confirm with Yukon and fulfill within a couple days. So before you buy (if you go with the Yukon master overhaul kit), maybe check with the vendor and/or Yukon about availability and timing.