I own a 1992 Ford F-150 short bed 4x4 with an automatic transmission. The truck now has only 18,000 miles on it. When I had driven it for a few thousand miles, a clunk developed when accelerating from a dead stop. The dealer then took the driveline apart and lubricated the slip yoke with lithium grease.
After a few thousand more miles the clunk was back. The dealer then installed a new slip yoke. The mechanic told me the noise will probably come back.
Using the Alldata information system I pulled up Ford Technical Service Bulletin: No.96-23-20. This bulletin recommends the replacement of the slip yoke and the attached U-joint. This redesigned slip yoke utilizes a high Phosphate Nickel coating on the splines to improve its sliding characteristics.
The new yoke came out in 1996. So it's possible the one installed on your F-150 was not the updated version. If so, the noise may return. Dig up the service department receipt for the work and take a look at the part numbers. There are two different size slip yokes. The part number will be either E4TZ-4841-BB or F5TZ-4841-EB. If one of these numbers doesn't match your receipt, then head back to the dealer with the above service bulletin number and tell them your story. They might help you out even though the warranty has expired, due to the history behind the problem.