Crunching sound

When I shift from park to drive or reverse after start up, I get a crunching sound. I don't here during normal driving conditions. The sound seems to be coming from underneath the vehicle. Any suggestions on where to start my diagnosis?

Jeep set-up:
2001 4dr XJ
4.0, auto
3.5" RE Superride
ProComp Adj. track bar
31" BFG AT
RE transfer case lowering kit

Thanks for any help

That's a really open ended question. Have you considered getting under the Jeep yourself and looking for anything amiss?

it's prob. your rear ujoint. You're running 3.5" lift on a 2001 without a sye (at least your description didn't say you had a sye). Your rear driveshaft angle is prob. maxed out and it's wearing your ujoint. The tcase drop alone isn't a solution. Install a sye and be done with it.

That would be my first guess.

Thanks Jeepster. I've been rechecking all the bolts from my lift to make sure they were all torqued, never thought to look at the drive shaft U-joint. Even if it's not the lift, It's prolly due at 112k. I've already replaced one at my front axle.