Universal joints

I don't know what "cactus" means

You must remove the shaft, IE unbolt the rear drive u bolts/ bolts, gently pry out of the rear yoke, and be careful not to lose the rear caps.

Give all joints the "wiggle and move" test to check for dry spots and crushed bearings. Just because the two removable caps on the rear look OK and show grease, does not mean both the other are OK