As with all things mechanical, there comes a time when the life span of even a well-engineered product ends. This can be due to excessive use and load or, for this article, a weak link in the chain. Any loyal, proud owner of an '80s-model Ford Ranger can brag about its reliability, as well as its durability. Very little bad could be said of the mighty Rangers, except for one weak link: the tendency of the rear driveshaft to break off where it meets the differential. This is a common problem that occurs in both two-wheel- and four-wheel-drive models, lifted or not. The stock 1210-series U-joint is not strong enough to handle the power going through the driveshaft, and, eventually it breaks, usually with the slip yoke or flange also suffering damage.
To fix this problem, you could replace it with new OE parts or you could have a new driveshaft custom-built, stronger than stock in the critical stress areas. The second option would be our recommendation if your Ranger is lifted and you do a lot of off-roading. The downside to this path is the cost and down time. Custom driveshafts are not cheap, and they take time to build. The third and most viable option would be to upgrade the rear U-joint of the stock driveshaft. This is faster and, by far, more economical for the average enthusiast.
We called upon on our local driveline specialist, Unitrax in Anaheim, California. These guys are in the heat of the battle everyday and offer the expertise to solve our problem with an affordable solution. The heart of the upgrade is the new Spicer 1310-series U-joint. This replaces the stock 1210-series, giving the pivot area more strength to withstand the daily beating it receives. To handle the mounting of the 1310-series U-joint, a stronger slip yoke and mounting flange, also made by Spicer, are installed in the battle against another break.
The Unitrax crew fixed the wounded Ranger in less than two hours, leaving the rest of the day open to get back to the action -- this time, though, with the feeling of reliability. Our short-term evaluation of this simple, affordable upgrade was a thumbs up.
SOURCES
Dana Corp.
Dept. OR
P.O. Box 321
Toledo, OH 43697
(800) 729-3262
www.dana.com
Slip yoke, flange, 1310-series rear U-joint
Neapco Inc.
Dept. OR
Box 399, Queen & Bailey Streets
Pottstown, PA 19464
(800) 821-2374
www.neapco.com
Front 1210-series U-joint
Unitrax
Dept. OR
1280 N. Sunshine Wy.
Anaheim, CA 92806
(800) 622-4327
(714) 630-4327
www.gounitrax.com
Installation
 1. Since the shaft was already...  1. Since the shaft was already removed, the first step was to get a center-to-flange measurement. This was needed to ensure that the repaired shaft ends up the correct length. |
 2. The break in the driveshaft...  2. The break in the driveshaft occurred here, where the U-joint rode inside of the slip yoke and the flange. |
 3. The stock slip yoke was...  3. The stock slip yoke was removed by pulling it off the spline of the stem. |
 4. Here, the two yokes can...  4. Here, the two yokes can be compared. The Spicer slip yoke on the bottom is made thicker, especially around the bearing holes. |
 5. To accommodate the 1310-series...  5. To accommodate the 1310-series U-joint, a Spicer flange (right) was used. The new flange is thicker and big enough to hold the new U-joint. |
 6. Since a new U-joint was...  6. Since a new U-joint was being placed in the rear, it was smart to replace the front components. During the break, it's possible that the front U-joint was damaged. To install the new U-joint, the CV joint was removed from the shaft, then the U-joint and flange from the CV. |
 7. Next, the U-joint connected...  7. Next, the U-joint connected to the shaft was removed. |
 8. With the driveshaft stripped...  8. With the driveshaft stripped down, it was placed in a lathe. |
 9. Once in place, the shaft...  9. Once in place, the shaft was checked for any major surface dents with a dial indicator. |
 10. The new slip yoke didn't...  10. The new slip yoke didn't have a master spline like the stock unit. For the new one to line up, the weld around the stem was cut with a circular saw. |
 11. Then the new slip yoke...  11. Then the new slip yoke was installed and tapped with a hammer to help line it up with the other end of the shaft. |
 12. Once the correct placement...  12. Once the correct placement was achieved, the stem was tapped into place and checked for imperfections. |
 13. The stem cap was tack-welded...  13. The stem cap was tack-welded in place. |
 14. And then it was fully...  14. And then it was fully welded in place. |
 15. The result is factory...  15. The result is factory looks and strength. |
 16. Before the new U-joints...  16. Before the new U-joints were installed, the bearing caps were removed. |
 17. First, the new 1310-series...  17. First, the new 1310-series U-joint was positioned in the flange. |
 18. Once in place, the bearing...  18. Once in place, the bearing caps were pressed in. |
 19. Then the U-joint and flange...  19. Then the U-joint and flange assembly was attached to the slip yoke. |
 20. Snap rings were installed...  20. Snap rings were installed at the ends of the bearing caps to help hold them in place. |
 21. To keep the stem area...  21. To keep the stem area clean, the original dust boot was reinstalled onto the driveshaft. |
 22. The Spicer slip yoke was...  22. The Spicer slip yoke was equipped with a zerk fitting that was tapped into place. This will make future lubrication of the yoke fast and easy. |
 23. After lubing the new slip...  23. After lubing the new slip yoke's splines with grease, the slip yoke was pushed onto the stem of the driveshaft. |
 24. With the rear finished,...  24. With the rear finished, the front of the shaft was next. A new 1210-series U-joint was positioned into the driveshaft. |
 25. Then the bearing caps...  25. Then the bearing caps were pressed in to hold the joint in place and allow for movement. |
 26. Next, the CV joint was...  26. Next, the CV joint was positioned over the U-joint and held in place. |
 27. After installing the centering...  27. After installing the centering springs, the flange was held in place on the inside of the CV joint. |
 28. While holding the flange...  28. While holding the flange in place, another 1210-series U-joint was put into place. |
 29. Once in place, the bearing...  29. Once in place, the bearing caps were pressed in and held with snap rings. |
 30. The completed driveshaft...  30. The completed driveshaft was measured for accuracy. In this case, we were exact, 45-3/4 inches on the center of flange measurement. |
 31. The front of the driveshaft...  31. The front of the driveshaft was inserted into the yoke of the tailshaft, with the U-joint resting in the cradle. |
 32. Next, the rear flange...  32. Next, the rear flange was lined up with the holes for the differential mount. |
 33. With everything in place,...  33. With everything in place, the bolts of the tailshaft yoke were tightened up to the flange at factory specs. |
 34. The four bolts for the...  34. The four bolts for the flange mount were installed and tightened to factory specs. |
 35. The newly rebuilt shaft...  35. The newly rebuilt shaft bolted back into its original position. The addition of the stronger U-joint, slip yoke, and flange had no affect on the overall length. |
 36. The new components were...  36. The new components were stronger than the originals and will last a long time. |