new to post, front and rear u-joint on a 1991 b2600 cab plus going bad, center joint good, was told cannot service u-joints , dont believe this, has anyone replaced u-joints does anyone have part #'s. would appreciate any help, thank you

 

Can you take a picture of the driveshaft, specifically around the u-joint areas? You can't service a u-joint, but you should certainly be able to replace them.