grease guns and zerk fittings.

AFAIK all u-joints are serviceable, even the ones without zeros, you just have to tap the zerk on with a drill and thread cutter. But that's something most people want to deal woth.

More to your question, all fittings (on-point, ball joint, etc) should be greased regularly to evacuate the old contaminated grease, which will reduce wear on the part.

I usually pump slowly until clear grease squeezes out. You should hear alot of soulds (squishing or very light popping) as the new geearease displaces the old. This is normal, but a bit disconcerting the first youn do this process.

Keep an eye on the rubber boot as the grease pushes through. Sometimes it will bulge a bit before it starts to ooze out. If it doesn't escape around the seat, after about 1/4" of bulge in the rubber, stop, gently squeeze the rubber boot until you get some to ooze out. If you squeeze too hard, pump too fast, or just ignore the bulge, there is a slight chance of having the rubber seat slip off of its recess.

If for whatever reason, you can't get the grease to ooze out, just stop there and try at your next interval. The movement of the joint, among with the new grease should eventually things moving, and you'll see the grease coming out some point, after a few cycles.

Once you get the grease to start oozing, continue pumping (again slowly)until you see clean grease come out.

Finally, wipe off old/excess grease with a rag at each zerk.

These really ease maintenance things can seem hard at first, but are worth the effort.

The only time I've had issue was after buying a vehicle that was not service before, and the boots were too far gone to do much with.

 

I did mine on my 2014 DCLB 4x4 and it was easier than I thought . What prob are you having