Unresolved X axis hanging at certain spots

Hey guys, my X axis started hanging randomly earlier this week. It does it in the same spots towards the end of each side, and hangs whether it moves from the stepper or if I slide it by hand. It seems to only do it while moving from right to left. Left to right slightly stutters some times, but generally seems okay. I don't see anything to tighten that could affect it. I've lubed the rails and checked the level with a square all the way around and the bearings on the extruder sled do not seem to have any play in them so I don't think the rails are misaligned. Did my stepper just crap out or am I missing something else?

 

Would the stepper driver affect it when I'm sliding it by hand though? And I'm guessing to check it I just need to pop one out that works and swap it with the one in question?

 

Ok so I just disconnected the belt and tried sliding it back and forth by hand. It's still sticking in the same spots, going from right to left only. I'd say that rules out the stepper motor. Should've thought of that sooner. Maybe the bearings on the extruder sled are bad? Or would it be sticking no matter which direction it was moving? I've triple checked the height and level of the rails in 8 spots (4 each rail) and everything seems to be right on.

 

Update, I pulled the rails and carriage assembly off and took apart the left side so I could get the carriage off the rails. Just for the heck of it, I saturated the inside of the bearings with white lithium grease. Then I just kept running it back and forth on the rails. Seemed to get it back to working order again. Correct me if I'm wrong, but this further proves the bearings are bad, right? They should be self lubricating so having to lubricate them instead of the rails seems like a red flag. At least it'll get me up and running enough to finish this current project. It's about time to do some upgrades anyways. Maybe I'll finally bite the bullet and move to a dual extruder and the chimera carriage. Thanks for talking this out with me. I tend to way over think oddball stuff like this.