I have had this problem for several years in my 2007 V6 steering. I heard and felt the "slight clunk" every time I drove the RAV4. It was out of warranty when I saw the service bulletin. Two weeks ago I decided to try my own fix. I have driven regularly for 2 weeks and not heard or felt a clunk. It is wonderful. Here is my fix, I removed the "Steering Intermediate Shaft", inspected it and found no specific problems, no looseness or binding. I thought the problem might be that the lubricant in the sliding connection had worked out. I pushed as much of the original lubricant back into the splined area as practical and then added a limited amount of WD40 spray lubricant to reach into the splined section and also soften the original grease. (the 2 sections of the "Steering Intermediate Shaft" could not be readily separated) In order to best get the lubricant into the sliding section I removed the steel cup which contains a seal at the top of the tubular sliding member. I put a screw driver against the edge of the cap and tapped it with a hammer to slide the seal cup off of the tube. At the end I gently tapped the seal cup back in place.
A possible short cut on this procedure that might work is to spray WD40 or something similar into the sliding section without removing the steering shaft. I believe for this to be successful you would have to remove the seal cup so lubricant can be added at the upper end of the sliding section.
To remove the steering shaft I followed the procedure given in the service bulletin at first. I was not able get to the bolts to remove the shaft with the steering wheel in one position straight ahead. I then very carefully used a marker to index each of the joints that I was removing to the shaft it was on so I could put each back in the exact same angular position. I do not know what problems are caused if you don't get them back exactly as they were. After marking the pieces I then rotated the steering shaft to a place where I could remove the bolt from the coupling. It must be removed not just loosened as it fits in a groove on the inner shaft to locate the coupling position lengthwise. Other than the lower plastic shield I removed only 1 bolt from each end of the steering shaft couplings and then was able to pry off the couplings and remove the shaft assembly. Before starting I removed the small dashboard panel immediately under the steering column, 2 screws and then just pull off from friction pins.
This has gotten long so I will stop. I will check back for a few days if there are questions. I do not have photos or any means to get them.
A couple of days ago I posted on the TSB thread for steering shaft clunk, details of a fix I completed on my RAV4 two weeks ago. For that two weeks the clunk has been completely eliminated. Because that post has not gotten any attention I mention it here hoping those with the problem will see it. I hope the link below will take you to that thread, provided you are signed in.