The past 2 years when I pulled my Cobra SX drives off my 97 Vista 278, I noticed the stbd gimbal bearing was "tighter" to move by hand than my port. The port gimbal bearing spun real easy by hand.
Today, after having my bellows replaced, I was about to grease everything up and put it back together. The stbd gimbal bearing is still tight and smooth, however my port side now isnt smooth to spin anymore

Good thing I checked it before I put it all back together!!
So basically, is NO roughness permitted with a gimbal bearing? Mine is smooth until I go to one spot and then theres a little bump... so little you can barely notice it. There is no play in the bearing that I could detect, but it IS much easier to spin than my stbd side. I didnt have any noise/water intrusion/vibration last year. My mechanic is charging me (***get this***) $30 (no missing zero's) to replace the bearing, providing I get the part. I will gladly hand that over!
Also - good idea to replace both at the same time, even if only 1 needs it? Or should I run the stbd gimbal bearing out until it too gets rough/easy to spin by hand?