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I installed some rear gears in my 2004 Silverado 2wd 10 bolt. I am needing some help, or someone to check my gear pattern to see what could be causing my problem. This is how I set up the rear end and a list of the parts I used.
GM 10 bolt 8.625
US Standard 4.11 ring and pinion
Yukon Dura-Grip posi unit
All new bearings and seals
Pinion shim .0035
Pinion preload .0037
Backlash set to .0007
The problem is that there is a gear whine most noticeable between 20-50 mph while accelerating or on the gas. Below 20 or above 50ish the noise is not as noticeable. Also during coast or off the gas there is no noise. Only makes the wine noise on tip in and under load. I have not pulled the cover to inspect the gears. and I have only put about 200 miles on the setup. The noise has no gotten any better or worse, since first drive. I think maybe the pinion is too deep? Here is the pattern.
The pattern looks slightly high and towards the heel of the drive side. Adding more pinion shim would move it deeper into the root and towards the toe. I'd probably add .005 to the pinion shim, maintain specified backlash and recheck.
Yes it was a brand new gear set. I was hoping maybe they would wear in some. But the noise has not changed after a couple hundred miles. Also read that “cheaper” gears are prone to a bit of wine. Thanks for the input.
New gears always focus on the drive side not coast side. Trying to get both set up ideal will just keep making you go in circles. I’ve had good results with motive gears and true Yukon. Never tried the cheaper ones I applaud the effort in trying to get them right before breaking it in. Did you happen to swap the crush sleeves for solid spacers as well?
I used a regular crush sleeve. I used motive 4.10s in my Camaro, set up was similar and I never had any noise from them. Im afraid it may just be due to using a cheaper gear set. Sometimes you get what you pay for.
I installed the same gears (USA Standard 4.11 8.5") a few months ago and have a little bit of noise too. Initial installation showed a good pattern with a 0.0305 pinion shim and 0.0065 backlash. First drive was fairly quiet but grew noisier thru the break-in. When I changed the fluid after 700 miles, the backlash had grown to 0.074. The kit I was using had a bunch of really thin shims and I guess I had just gotten some trash in between them and the backlash grew once it got washed out. Reshimed back to 0.0060 and the noise lessened significantly but still have a slight noise around 50mph. However, my noise isn't traditional gear whine you normally think of, it is more high pitched almost like turbine noise on a jet plane. It hasn't changed in a couple thousand miles and I can't hear it with the radio on so I'll just live with it. In doing some research on the USA Standard gears, I found accounts of some of them being noisy no mater how well they are set up per professional installers. Apparently they are Yukon gears that didn't meet quality control standards for tooth finish which accounts for the noise.
Thanks for the information. That’s what I was afraid of. I also did some research on the USA standard gears and for similar concerns. I may just let them be for a while, change the fluid after a few more hundred miles, and see what happens. I’d hate to keep adjusting them to end up with the same result. The noise isn’t so loud that the exhaust and radio won’t cover it up. I just want everything to be done right on the truck. I should have went with a better gear set. But it is what it is.
09-17-2018, 03:36 PM
Gear pattern / gear whine
