U-joint help

Ive got an 06 Tacoma and im hearing a grinding sound, at first i thought it my tires cus i just got them rotated but im pretty set on its my u-joints. im not sure how to check it but i thought it was if it has play in it then it means its bad so i did that and there is alot of play in my drive shaft. is that how u check u joints or am i just an idiot

 

Grease them and see if it goes away or changes.

 

If you mark the drive shaft and then remove it and turn the joints back and forth for hard or tight spots and play, if there's any replace them all or take to good mechanic, just remember to paint pen mark all sections of the shaft and joints so it will be in balance.