"....but I think what is happening is that when you decelerate the spring is flexing a little and the pinion is going down just far enough that the yoke goes out just far enough to get a little sloppy."
^^ that. Awhile back I posted some measurements I took of the output shaft (231 t/c) with the vehicle sitting on level ground. OAL of the output shaft splines is 3.25". Exposed splines with driveshaft installed is 1.25" leaving 2" of splined shaft in the slip yoke. I've got the proper angle to within 1.5 degrees. It's lifted 2 1/2" in the rear and 2" in the front. Always thought that only 2" of the output shaft in the slip joint wasn't ideal. And the higher you go the less you have.
As far as greasing the slip yoke goes I put enough in that it was all I could do to collapse it enough to get the rear u-joint in to the yoke. If it helped with the issue it wasn't by much.

 

It doesn't always work, but every once in awhile it does. But 2" isn't all that much. I am still of the opinion this is the issue. It is common with that type of tail shaft to have that happen

 

OK .... next subject: Slip yoke eliminator and Double cardan driveshaft.
Which one and where to get it?

 

That depends on what you are willing to pay and what features you want.

 

I'am willing to pay for what I need.
I don't know about features.
I won't be wheeling in bad spots.
no rock crawling.
With that being said what would you want Four Point Three

 

Well I am an Atlas fan. Heaviest output shaft, provision for a driveline parking brake and speed sensor. However the cheapest is going to be what is called HacknTap. But you need to be skilled with a drill to drill and tap your tail shaft. I have known one to fail so there is that. So I think the best solution for you would be any of the kits that give you a new tail shaft and yoke. Many of the kits allow yo to use a stock front XJ drive shaft and can save you some bucks unless you want an extra heavy driveline that is very hard to bend

 

I agree. Adams leaves no less than 3" in the spline joint on their driveshaft.

 

Advance Adapters sye kit seems to be the most popular. Both Wood's and Adam's offer it with their driveshaft kits. I just received the Adam's sye kit w/driveshaft last week. Had thought about using an OEM front driveshaft but if it's too short or too long and/or would need balancing your into a few bucks to make it work reliably.
https://www.adamsdriveshaftoffroad.c...shaft-package/

Here is another option but I couldn't find enough info that I felt comfortable in giving it a try:

 

Well its time to start pinching pennies.

 

Just like the rest of us