I have problems with my cv axles too.
Tired with this, I began to find a alternative to solve this problem.
Here in Brazil we found a solution! It's easy and you can do too!
To eliminate your problem forever, you have to buy TRAIL GEAR Longfield™ 30-Spline 4340 Chromoly Super Set + 3. Your IFS system will be OEM.
OK! I know that you can say me: "But our 4Runners are 27 splines"!
So, how we say here in Brazil here is "the jump of the cat": In one side will be 27 splines, as product as sold! In the other side, it came 30 splines. Thus, this side you need to arrange for a turner do 27 stretch marks as in the original, eliminating those 30 who came.
Could understand?
After this modification has a 4Runner (here called Hilux) here walking tires 40 "and still is for two years without breaking.
Another tip that the owner of this car gave me was that the hoods must clothe them with duct tape, so that they never tear and prevent dirt from entering the grease, which increases the risk of breakage!
Sorry my mistakes!
Thanks and I think that it can help you!