Service - Ball Joints and the Installation
Here we are with the tire off and ready to go at it. I first jacked up just the one side as shown here, but later found it was better to jack up the whole front end so that I could turn the wheel in order to get easy access to all 4 bolts of the ball joint.
Here is the ball joint for a 93 Hummer fresh out of the package. Nice and tight.
Looks easy right, just take out the bolts and pull out the ball joint. Not so. Never taking out one before I tried to pop it out with the tire tool, the tired tapping the large bolt/post with a small hammer (see small hammer in photo below). That sucker was in there. Next I tried I tried a 16 lb hammer, just a tap did it and out it came. I should have used and puller to separate the lower ball joint from the geared hub, but.
Installed the new ball joint and lined it up, and bolted into place. The bolts are then tightened down to 37 ib-ft. Then intalled the ball joint into the hub with the slotted nut. Tightened nut down to 73 lb-ft and install a new cotter pin. 

CAUTION: Do not loosen slotted nut to install cotter pin. This could result in damage to equipment and not seat right. 

Grease lower ball joint (and the rest of the grease fittings while you are at it) and you are complete once your wheel is mounted. The 8 lug nut on the wheel are to be tightned down to 110 lb-ft . 

As I said, it was easier to work on with both front tires in the air. 

The job only took about 15-25 minutes for each to complete the change out of the lower ball joint. The upper ball joints should be as easy. 

Once it was completed and road tested I had no more squeeks from the front end. 

If your ball joints do not have the grease fitting, change them out, the idea of the needle sounds good, but does not get to the bottom of the ball joint where it is needed. 

Here is the old ball joint after I it up to examain just how bad it was. The ball joint here was not as bad as some I have seen. Here the teflon cup that the ball sits in as not warn though yet as they are when they are really squeeky. This one here was squeeking, but not as bad. As you can imagine greasing with needle, and injecting the gease into the rubber boot of the ball-joint will get grease at the top of the ball, but not down below where is it needed. A Grease fitting really makes a differance in the life of a ball-joint on a Hummer.
Here is a close-up look at the ball and as you can see it is not smooth, but pitted like it may of had water in it at one time and rusted, but 100% sure how that would have happened. The rubber boot that was one this joint appeared to be okay, so just how water got in if it did, I do not know, but it does.