Measurements

• 1). Measure the transmission and rear axle yokes and maximum drive shaft length. Measure both the transmission and rear axle yokes from their spline ends to the center of the universal joint openings. Measure the length of the polished seal face on the transmission yoke.
  
  
• 2). Jack the rear of vehicle until the wheels just leave the ground. Slide front yoke into transmission as far as it will go. Note position and slowly slide out until just one inch of the seal face stays inside the transmission seal. Note this position and measure the difference in protrusion.
  
  
• 3). Install rear axle yoke. Rotate both so that their universal joint holes are horizontal. Measure the distance between centerlines. Measure the vertical distance between axle bottoming snubbers and frame.
  
  
• 4). Calculate minimum drive-line length. Square the vertical snubber distance from Step 1 and subtract from the square of the center line distance between yokes also from Step 1. Take the square root of the result. This is the minimum drive shaft length. The difference between the maximum drive shaft length and minimum length must be less than the difference in protrusion for the two transmission yoke positions above or severe vehicle damage can result when driving.
  
  
• 5). Calculate drive shaft steel tube length required. Measure the distance between the weld lands on the shaft yokes and the center lines of their joint openings. Subtract these from the minimum drive-line length measured above and the result is the length to which the drive shaft tube needs to be cut.
  
  

Fabrication

• 1). Cut drive shaft steel tubing to exact length calculated above, making sure the cut is exactly square to the tube length. Carefully file off any burrs, and smooth the end of the tube.
  
  
• 2). Fabricate the drive shaft center assembly. Slide the two drive shaft yokes on the tube until seated. The universal joint openings in both yokes must have the exact same rotational orientation. Weld carefully around the entire circumference of each tube yoke joint in one smooth operation.
  
  
• 3). Join transmission and rear axle yokes to center shaft assembly by installing universal joints per instructions. Use either a press or a heavy vise to press joint cups.
  
  
• 4). Spray the entire assembly with rust inhibitor and wipe off excess. Have the shaft straightened and balanced if the vehicle is intended for open road use--this requires special equipment.
  
  
• 5). Install in vehicle and measure drive-line angles using level protractor. The front and rear universal joints must reconcile exactly the same angle or severe vibration will occur at speed. Adjust rear transmission height with shims to adjust.
  
  
• 6). Road test vehicle.