Need new U-joints or not?

[maddawg308]

Okay, going to install the rear driveshaft this weekend, but how do you know if I need to install new U-joints? The ones I have seem to work okay, but are a little rusty and dirty. The joint seems okay, though.

 

[gimpyrobb]

If your asking about the icecream truck, I would say, pump some grease in and go! I try to carry at least one in the parts box.