hey guys just recently had both front tie rods replaced w/ 4wheel comp alig. and now when i put it in 4wd auto or 4wd hi get a slight vibration from front axle at 25 to 35 mph. nothing when in 2wd could it be diff. fluid? I just had shoulder surgery so i cant get under to check anything and wondering what it could be so if i bring to garage tell what to check so i dont have to pay for lot of unnessesary checking all you guys been great on diagnostics on my last questions so thanks in advance