Those of you with Yukon or US Gear ring and pinions - looking for your input

[acammer]

As it's about time to get the car out of storage I'm making plans for 2019 mods, and on the top of the list is to have the rear-end rebuilt with a TruTrac, and hopefully get things nice and quiet.

The Motive gears I have in there now are pretty noisy. I can't really blame it all on the gears, I had a crush collar fail and made a 200 mile drive home with minimal pinion preload, so that was likely not a fun experience for them and likely did some degree of damage to the gear faces clanking around the whole ride home. I got everything reshimmed, nice pattern, perfect backlash, but the noise is just awful. The LPW Support cover, BMR Pro diff bushings, and Pegasus solid aluminum sub-frame bushings don't help. The stock posi is also starting to really give up in the water box at the track, so it's time to right some wrongs in the rear end.

So, I'm looking at my options for 4.10 ratios, and there are essentially 4 choices from what I can find - Richmond, Motive, Yukon, and US Gear. I had a set of Richmond's - tore a few teeth off the ring gear, not looking to repeat that. The Motive's have a pretty well known reputation in 5th gens as taking abuse well (several of the all motor fast guys have run these with great success) but also have a reputation for being somewhat noisy - that's been my experience too. US Gear and Yukon both have pretty good reputations for reliability and noise outside the 5th gen community, but you can't find much/any information at all about them in our little 8.6" rear.

I'm inclined to just buy Motive again because it's hard to argue with the results in longevity that the guys that send these things through super aggressive launches time and time again. But, I have the trifecta for noise transfer, and want to not hate the car every time I get up on the highway for more than 90 seconds, so I'm looking at options. Price matters, but is secondary to getting a good quality gear that's tough and quiet. So, if you've got a Yukon or US Gear I'd love to hear what you're experience has been - mileage on it, ratio, usage (do you drag race the car with sticky tires), etc.

[CamaroCracka]

I don't have any Camaro specific experience, but I have used Yukon and US Gear products on my mud truck without fail. Yukon's locker is even a bit more streetable than the Detroit they purchased the rights to. Pretty sure Yukon bought US Gear, but that doesn't necessarily mean the gears are the same. I've had good luck with both.

[bkevind]

Yukon 4.11 here. Mine are noisy. The sound is really amplified by solid cradle bushing, hard diff bushings and LPW diff cover. I had it done all at once with a TrueTrac, so I can't compare noise levels just between stock and the Yukon. But I do think the Yukon's are making more noise than they should be. With the sound amplified, it's terrible as a highway car. Quick trips are fine but nothing more.

It could be the installation, or the initial break in that made them noisy, but I trust the shop's experience.

I drive hard on the street and drive it very hard on track. About 1500 street miles, and 2.7 track hours.

1 track (road course) weekend so far, worked out fine.

[acammer]

Thanks for the input guys. I do believe the install has everything to do with how noisy they end up. I finally have a drive line shop that I'm confident in, so hopefully this will be the last time!

[GRNFLSH]

acammer, looking forward to finding out if the gear swap helps with noise. I just bought used diff with 3.91s and truetrac and added LWP cover and solid bushings at the same time. The noise is much more than expected, so I’m trying to decide if I need to drop the diff and dig into it.

[acammer]

Originally Posted by GRNFLSH

acammer, looking forward to finding out if the gear swap helps with noise. I just bought used diff with 3.91s and truetrac and added LWP cover and solid bushings at the same time. The noise is much more than expected, so I’m trying to decide if I need to drop the diff and dig into it.

I'll keep you posted - it's in the shop as we speak for the Yukon 4.11, all new Timken bearings, and the Trutrac. My driveline shop is confident they can get it to run quietly long term. Apparently, the Yukon has a 2yr warranty through the vendor my shop is using - I'm a little suspicious about that, but I have it in written form from them, so I'll hold them to it if I have problems.

I gotta say it won't be hard to make it better than it was - I had the cutouts closed and going up the highway at 75mph is absolutely BRUTAL on the ears with the mis-worn Motive gears in there. I don't really expect it to run silent with solid metal subframe bushings, BMR track bushings in the diff, and the LPW cover - but I do expect it to be tolerable. As a last ditch effort I may look at swapping differential bushings to something softer.

[zlathim]

Good luck, Andrew. Let me know how it sounds when you pick up the car. My gears are still howling away, but they seem to be holding together.

[Dbunch9]

Curious to know how it goes, i'll be buying a Yukon 4.11 when i can

[Bradlyj8]

Well... did it work out?

Originally Posted by acammer

I'll keep you posted - it's in the shop as we speak for the Yukon 4.11, all new Timken bearings, and the Trutrac. My driveline shop is confident they can get it to run quietly long term. Apparently, the Yukon has a 2yr warranty through the vendor my shop is using - I'm a little suspicious about that, but I have it in written form from them, so I'll hold them to it if I have problems.

I gotta say it won't be hard to make it better than it was - I had the cutouts closed and going up the highway at 75mph is absolutely BRUTAL on the ears with the mis-worn Motive gears in there. I don't really expect it to run silent with solid metal subframe bushings, BMR track bushings in the diff, and the LPW cover - but I do expect it to be tolerable. As a last ditch effort I may look at swapping differential bushings to something softer.

[acammer]

Originally Posted by Bradlyj8

Well... did it work out?

Good question - thanks for reminding me to follow up. Here is the 1 year report on the Yukon's. Overall I'm good with the Yukon gears. They went to the track on 4 occasions in 2019 and made a total of 16 passes, with an average 60' time of 1.77, and a best of 1.66, all on drag radials - NT05Rs in the spring, and DR2s in the fall. They also sustained plenty of test hits out on the street. The trutrac is fantastic - I didn't realize exactly how much the LSD was giving up on me until I got the trutrac.

As far as the noise - well, it's better than the abused Motive gears, but it's still very present. The shop went through great lengths in setting, and resetting, and resetting AGAIN the lash - they have perfect lash, a beautiful pattern, but they still aren't quiet - really not much different than the Motive's (before I hurt them - after I hurt them they were awful).

Having had a few different gear sets in the car now, I'm confident to say that with an LPW cover, solid aluminum sub-frame bushing, and BMR Pro hard poly, it's never going to be quiet. And, that makes sense - you've basically removed all dampening between the ring gear and the body of the car - the LPW has actually made it a much more direct connection to the subframe with the load bolts. I haven't tried softer differential bushings yet, that may be something I consider some day. For now, I choose just to live with it.