That is a gkn, style u-joint, some have external snap rings others have internal clips, depending on what serial # drive you have the snap rings come in different thicknesses for proper fit of the u-joint. I believe the rebuilt u-joint is a newer serial number due to the smaller size of the cap, both will work the same. As far as the top cap goes; the gear back-lash should be .009-.015 with the proper checking tools. If the drive you are using is driving the lower gear forward you will be ok, but if it's the top gear driving you forward, it needs to be checked.Do you have a local shop that is qualified to do this? I can help if not.