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Doing my first diff rebuild + gear swap and would love to get some crowdsourced knowledge to help me out. Went through the process and got her out on the road. Have a slight whine under light accel between ~48-60 mph, getting louder as I approach 60, then disappearing above. No whine at any other point under accel, no noise present under hard accel. The coast side is silent. Have ~75 miles on this gear set at this point running with synthetic 75w-90. I know there is traditionally debate on noise that higher gears may make (and whether that is to be expected or not), however, there are plenty of 4.10's in OEM cars that are quiet and I would rather not settle if I can avoid it. Generally, I see it as noise = friction = heat. See the below info + patterns and let me know how your expert eyes see it. As always, your insight is greatly appreciated.
Looking forward to your feedback. My first thought is to get backlash up around .006 and see if I make progress with the noise since that is the easiest thing I can do before getting to the pinion depth.
Specs:
Have an AAM 4.10 gear set (2 cut gears / face hobbed) paired with an eaton truetrac. Full Koyo rebuild. OEM pinion shim is a 0.037. My final setup is bottom right in each pic, running at a .037 stock pinion shim and .004 backlash. In case it is hard to read, pinion depth changes in order are 1. .038, 2. .037, 3. .035, 4. .037. I currently have the bottom right running on my truck producing the above-resulting whine.
Drive Side: (toe is on the right side of every image)
Coast Side ((toe is on the left side of every image)
10-08-2021, 11:37 AM
AAM 4.10 Pattern Check, Whine Under Light Accel
