How do I tell if deck spindle(s) is bad?
 

Seems like my mower is pretty loud anymore when the deck is engaged. I pulled the deck but everything seems tight. If a spindle was going, would it have some obvious looseness to it?

Or maybe just a loud noise

The only loud noise I hear is you.

What deck do you have? It could still be bad and not be loose. In my experience with the ones with the tapered roller bearings, they get noisy before they get loose.

First off it would be helpful to mention what you are working on.
We are not mind readers, you might know what you have, but we do not.
To generalise:
Have you been keeping the deck bearings lubricated ?
Have you checked the idler pulley bearings ( or pullies) if more than one.
Did you take the belt or belts off the deck so the spindles are free to turn individually?
Does one or more feel "rough" and make more noise the others?
Did you use a mechanics stethoscope to check them for unusual noise?
And as OZ cub said Just a loud noise is a poor description.
A patient asking a doctor why they are hurting is not going end well without
information.:bigthink:

You asked for help and when bearings go they can scream , so your comment is one that reflects your lack of understanding
Cub Diesel Fan and Ol George both concur with not being able to diagnose your problem without a little bit more polite information
If that upsets you so be it

You were being a smart ass and got called out on it. Admit it.

Sorry, I assumed a spindle is a spindle. I just have the stamped deck on a Enduro Series XT2 LX42.

AFAIK, the bearings aren’t greaseable.
The pulleys seem good. There is a very little bit of play.
Yes the belt is off.
No, neither seems rough.
I didn’t use a stethoscope.
Pretend your a veterinarian and you need to go by the symptoms.

Take the deck belt between the spindles off, then check if the spindle assemblies are securely attaches with all the belts and if the spindle has any up and down or side to side movement. easier to check without the horizontal tension of the deck belt.
If you rotate the spindle slow or quickly do you feel any tight positions or unevenness from a bad surface on the bearing or bearing race.
Take off the blades and check the centering of the blade and the balance of the blade, unbalanced blades will cause the deck to rumble and vibrate.
check the tensioner pully and see if its bearing is smooth and the tensioning mechanism is free to move.