I have a 2008 4x4 V8 4Runner with 32,000 miles and have been experiencing the drive shaft thump issue for about the last 25,000 miles. I have tried several times in the past to pump grease into all the zerk fittings along the drive shaft with mixed results. It wasn't until I read the previous post by Gordo that I realized why it wasn't working.
Everyone emphasizes that you only need a couple pumps of grease at each location, or else the grease just ends up spraying the bottom of the truck when you drive. That may be true, but it is causing everyone to insufficiently grease the slip yoke on the rear drive shaft.
I performed the "arkie 6 fix" as described by Gordo as follows:
I connected my grease gun to the rear drive shaft slip yoke zerk fitting and pumped about 20 shots of lithium base molybdenum disulfide (moly) NLGI#2 chassis grease into the fitting. The last 6 or 7 shots visibly caused the slip yoke to expand by an inch or two. Then I got on the rear bumper and jumped up and down several times to cause the slip yoke to compress and decompress. This caused several tablespoons of grease to squeeze out of the slip yoke seal. Then I pumped a couple more shots of grease into the fitting and a little more grease squeezed out, which I wiped clean with a towel. I didn't feel the need to remove the zerk fitting to allow any more grease to escape.
That's it! And unlike previous attempts which only caused subtle improvements in the problem, it has completely resolved the issue.
As Gordo emphasized, it takes a lot of pumps with the grease gun for the grease to work its way into the splines
(pic) and alleviate the binding problem. The "arkie 6 fix" can successfully coat the splines with grease without having to take anything apart.
I have driven several hundred miles without even the slightest thump in the drive shaft. I will update again after I have driven several thousand miles to confirm that the thump hasn't returned.