Anything besides diffs make a cracking sound?

[ICUBoy]

Thanks boys.
The sound is loudest and most consistent when braking heavily. It does happen at times at WOT but less loudly. If I pick it up off the groud it makes the noise when changing form forward to reverse (at speed- ouch!). I am contemplating new diffs but financially not a great time for the (beautiful but pricey) hybrid bulks and HB Lightning diffs. Thanks again fof the advice!