bears4x4
grease monkey
I got the ok for the misses
now waiting on test drive by brother, 
I test drove a 7.3 psd along time ago before I bought my current truck and it had the same symptom as yers. Sounded nasty at idle but as soon as you brought the rpm's up just a lil bit sounded great. Everyone on here said it was probably the torque converter. Sounds like a bunch of bb's rollin around. If you do the work yerself would be cheaper.
450k+ ehhhhh condition, but 450k on drive line was the deal breaker for me,- this is why I can never go by what my dad says" never never correct info, how it went from 150k to 450k+ gots me,
i dont see a good thing comin from spendin 3100.00 on the 450+ mile truck,