a couple months ago, a friend and I replaced my drivehaft u joints (87 Cherokee Laredo stock ride height) I bought 4 new u joints and to my surprise, there was a third u joint on the front shaft. I only installed 4 new ones, because I had to have the Jeep on the road because its my daily driver. I had no idea there was a 3rd joint there. Should/can I replace it with another u joint (same part number as the rest of the shaft)?