How often do you guys check the fluid level in the transfer case?? A mechanic buddy of mine goes to auction close by and buys cars to resale. A couple of weeks ago he bought a GMC cc/sb gasser ( don't know what year exactly , guessing 02-07 ) and there was a strange noise coming from the front end when he tried out the 4x4. He narrowed it own to the t-case. Didn't see any signs of leaks so he cracked it open. IT WAS BONE DRY. He runs a garage and since then makes a point of checking all t-cases on vehicles getting the oil changed. My wifes 99 Tahoe is a 4x4 and has never leaked fluid from the t-case , it was 1.3 quarts low ??? WTF happened to the fluid ??