They're really easy to install. If I recall correctly, you'll need a 15mm and 18mm wrench.
You can jack up the truck on the rear differential, then place the jackstands on the frame. Then lower the axle so that the wheels are hanging in the air. But make sure to keep a very slight amount of pressure with the jack on the differential.
Unbolt and remove the OE shackles. Jack up the axle about 2" (you'll need to tweak it to get the leafs to line up with the new shackle). Then install the new ones with the leaf spring bolted to the top holes. Leave all four bolts loose for now.
If you look at the underside of the bed, just above the shackles, you'll see some sheet metal that you must fold out of the way. It's nothing major. This prevents the shackle bolt from rubbing the bed. You'll know what I'm talking about when you see it.
Set the truck on the ground, on a level surface. Then tighten all four shackle bolts. If you have a torque wrench, that would be ideal. Torque them to about 75 ft-lbs.
If you haven't already ordered the shackles, I'd strongly recommend that you use the Ground Force brand. They come with pinion shims to prevent vibration that is caused when drop shackles are installed. This is because when only the rear of the leafs are repositioned, it changes the pinion angle. The shims will correct that. If you do go that route, I can give you an idea of how to install them. They're very easy.
Also, the Ground Force shackles use urethane bushings which are more durable. You just have to apply some silicone paste to them when installing to prevent them from ever squeaking.
Last edited by EsJayEs; 02-01-2012 at 11:21 AM.