Ok let me explain the install first. I didn't actually install the gears into my diff I swaped one axle housing with 2.73s for another one with 3.73s. So gear was already set as far as pinon depth, backlash, preload, etc. Now the noise doesn't sound like a gear or a diff, which as far as I've always heard has a howling or whrrrring noise most promenant on deccel. You can here the noise the best on light throttle acceleration at cruising speed. It sounds like a "wum--wum--wum--wum" that increases with ROAD speed and no it's not my tires. Most of the guesses said it was probably my driveshaft, one even told me it was common for driveshafts to make noise with diff swaps?? Any input on this would be great.