I just learned a lesson that I thought I would pass along to hopefully save someone some maintenance time.

My machine developed a loud squeaking noise that appeared to be coming from the y truck bearings. With power off the truck moved fine but made a very loud squeak. I removed the y truck and checked the bearings but they all appeared to be fine. Re-installed the truck and tried moving it without the y belt attached and everything was fine, no noise. I then hooked the y belt up and the noise returned, disconnect the y belt and noise goes away, again I was positive the noise was coming from the truck even when moving all the way to the keyboard side. In a last ditch effort before removing the truck again I tried spraying WD 40 on the pulley on the belt tensioner and the noise instantly went away. All I can think of is the noise traveled down the belt to the truck assembly because I certain the noise was coming from the truck.