1997 GMC Truck help!!

if it's your dads truck he'l probably know by now. first thing to do is pay attention, instead of the cell phone or texting that you were maybe doing. You are gonna kill someone that way let alone yourself. Do the easy stuff and check for mud/dirt, etc on the wheeel as that will cause a shake. Otherwise it's something bent like a tie rod or other front end part. Check for a bent wheel as well...