01. Block and chock the front wheels so the truck cannot roll.
02. Break the upper and lower shackle bolts loose on both leaf springs.
03. Jack the rear of the truck up and support the rear axle with jack stands. Remove both rear wheels.
04. Look carefully at the angle of the driveline. Note that the driveshaft and pinion are almost perfectly aligned and straight. This will be important to remember later.
05. Raise the body of the truck by jacking it up from the frame (the towing package equipped trucks have an advantage here Ė just jack it up from the hitch). Raise it until the rear end is just about to lift off the jack stands. This will unload most of the spring tension from the factory shackles.
06. Remove the lower shackle bolt on the driverís side. Pop the shackle out of its mount so it can swivel freely. If you use a long screwdriver to pry it up, you will lessen the chances of getting your fingers pinched.
07. Remove the nut from the upper shackle bolt on the driverís side. The bolt will not slide out because the truckís frame is in the way. Carefully lower the jack on the frame until the top of the leaf spring (and shackle bolt) clears the top of the frame. Remove the bolt and factory shackle.
08. Install the shackle in the top of the leaf spring, being sure to orient it to match the factory shackle. Put the nut on the bolt and run it on until the bolt sticks through the nut.
09. Carefully raise the jack on the frame until you can slide the new shackle into the lower mounting spot. Install the lower bolt and nut. Snug but don't tighten the bolts. Lower truck to ground and torque both upper and lower bolts appropriately.
10. Repeat steps 4-9 on the passenger side of the truck.
I think it is safer and faster to jack up the truck fully from the rear diff, then place the jackstands under the frame, just ahead of the front spring hangers. This way, you can just raise and lower the rear end out of and into position as needed without having to move the whole truck up and down. The first time I did it I thought I could do it without removing the wheels....NOT. Once the wheels are off, it should take less than 15 minutes to do the job.