I have a 2015 Tacoma 4x4 dbl cab long bed. I have 56000 miles on it, mainly highway, I started to feel a thump in the front end at random times at random speeds. Had Toyota look at it, 8 hours later, they changed both front and rear differentials oil. Inspected the front end suspension for play and found nothing. I was sent on my way saying they could not find the problem, if it gets worse come back. I took the mechanic for a test ride and the thump happened a few times. He said "never felt that before". Called Totota nothing . Any suggestions for my next step.