Lifeliner Driveline Problems
I've had the driveline done 2x on my '75 Lifeliner (aka Medic 5), and it's the biggest repair I've had in 8 years of ownership. The second time was necessary after the U-joint seals started coming apart and the driveline started whining. I had driven it about 200 miles and was I was coming back through San Francisco after a big Burn Relay Code 3 workout. This second repair ended up being done for free, with a warning: change the angle of the driveline going into the rear end, or have the same problem again.
Due to age, old springs, vehicle weight, etc, the driveline may sag a bit (I was told 2 degrees). This deficiency was not mentioned the first time around.
One solution is to rebuild the springs and replace the shocks (the shocks on mine are air shocks). The other solution is to put 2 to 2 1/2 degree shims between the springs. These need to be steel shims, and they're available at many specialty 4 x 4 suppliers. I'll have to report on the progress, as another big Burn Relay is coming up soon.