Hey guys trying to diagnose a problem with my transfer case. at only speeds of about 59-61mph my transfer case makes a grinding sound almost, its completly speed related... slower or faster and there is no sound. it only happens when i push the gas pedal down over 25%. if I put pressure on the transfer case selector (very slightly pull it toward 4hi) it goes away mostly.Its a 231 transfer case. I'm thinking the linkage is out of adjustment again or something. What do you guys think?