XHD Leaf Springs

I crawled under the car Saturday morning, and tried to determine the driveshaft/pinion angle..... and it appears to be nowhere near the -7 degrees that are "recommended" for leaf spring setups. In fact, if I'm calculating it correctly, it appears to be +2.... So I ordered some shims, and longer U-bolts.

While under the car, I noticed that one of my exhaust pipes seems to be situated very close to the driveshaft..... and I'm wondering if the spinning driveshaft is (perhaps) touching the exhaust pipe - triggering the odd harmonic noise.

Since I'm doing this investigation on the garage floor, it's difficult to really see a lot of this stuff clearly, but when the shims arrive, I'll install 'em, and hopefully all will be well.

But I did consider the gears - or at least the gear lubricant, as being a possible source of the noise. I don't really think this is the case, as the noise didn't exist with the old springs.

Again, thanks for the advice. I can't wait to get this straightened out.