Lead screw vibrates/shakes while rotating

ToTo

The lead screw on the left ('home' side) of my A5 suddenly vibrates ( vigorously) while rotating.  I tried to untighten/retighten all the screws, but that helped only a bit and the issue is still there.  I removed the lead screw and it looks visually straight.  So I plan to  replace the lead screw with a new one, hoping it might be bent/warped that I couldn't see.  What kind of grease should I apply on it?  Would the kind of grease for garage door opener's threaded rod work?

Laser8302

I use the PTFE lube suggested on the WIKI

Samuel Pinches

For more info, see the wiki page here: https://jgaurorawiki.com/lubrication

ToTo

I bought a lead screw with description as "400mm T8 Acme thread, 2mm pitch, 4 starts, 8mm lead", tried installing it, and apparently it's not the right one!  Visually I can see the threads are cut at steeper angle (from the axis) than the original one (that means the brass nut travels more linear distance per turn).  I should have asked in this forum first before ordering it.  So what's the correct size of lead screw for the A5?  Thanks you all for giving me helpful info, tips so far.

ToTo

Well, since the replacement lead screw is not the correct one, and I had already removed the motor and the screw, I put everything back and decided to put some lube on the lead screw; and just like that, all the shaking/vibrations are gone!  all it needed was just some new lube!  I feel stupid that it was probably just a typical, simple problem and needed just a simple solution.  But the good thing is now I know what to do for next time (or even do lubing the screws periodically to prevent it from happening again).