I installed James Duff traction bars and that cured the slip bump on mine. Unfortunately, JD has discontinued its line of traction bars but you can get them from other companies like Warrior Products.
I have tried the regrease routine before and found that it was only effective for a few months, at best. If you want to try the procedure, it would be best to get a shop manual for your truck. This is a brief description of what's involved:
Remember that removing the rear driveshaft disables the PARK function on automatics. For safety, always set the P-brake and chock the tires. If raising the truck is necessary, use properly positioned jackstands of adequate capacity to support the truck; never work under a vehicle on a jack.
The driveshaft must be unbolted from the rear differential pinion flange. On a 4WD, it must also be unbolted from the transfer case. On reassembly, the bolts must be torqued properly. The 2002 S/M gives 82~83 lb-ft for the four bolts at each flange. If the bolts are not replaced, their threads must be recoated with threadlocking compound.
Before disassembly, always mark the position of the driveshaft flanges relative to the mating flange at the diff and transfer case. On 4x2's, which don't have a front flange, also mark the position of the driveshaft relative to the tailshaft housing. Reassembly must be done in the same orientation to avoid disturbing the overall balance of the system. Never hammer on a driveshaft or its components. The rear flange fits tightly on a pilot on the pinion flange of the rear diff and can be carefully removed by prying rather than hammering.
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The 4x4 slip yoke is contained in the front of the driveshaft with a boot covering it. After removing the clamps and boot, the slip joint can be regreased and reassembled with a new boot and clamps. The clamps are supposed to be crimped with a special dealer tool. You should use the factory tool or equivalent; if you decide to improvise, the clamps must be tight enough to retain the grease and exclude water and dirt.
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The only lube to use is the Ford PTFE (Teflon) grease sold specifically for this application. For the 4x4's, there is a "kit" which includes a boot, 2 clamps and a single dose of grease. I got these numbers from a post on RPS:
Steel drive shaft - F87Z-4K277-AA
Aluminum driveshaft - 4L5Z-4K277-AA
It would be best to confirm that these are the correct part numbers for your particular application. The dealer can check the Technical Service Bulletins to get the correct parts. There have been many TSBs on this but a recent one is:
04-23-7 NOV 04 Driveline - Thump/Clunk on Acceleration/Braking
