"Does that make them satisfactory for synchromesh or synchronized transmissions?"

The article addresses the issue with using GL5 in a synchronized gear box.

FYI On a GEN1 and GEN2 there are no synchronizers in the transfer case to have a wear problem with. There are bronze thrust washers. However, the loading and heat level are not sufficient to cause any problems. I have never had the transfer cases apart on the later models.

The transmission is a different story and GL5 can reduce synchro life.

87 Turbo Intercooled Raider, roller cam, torsen rear diff, LSD front diff, lockup auto with modified converter, V6 brakes, low transfer case gears...