After going round and round with this stupid front end vibration mess on my 2004, I am changing out the bearings and axles again.
So far, tackled the driver side.
One thing I noticed, is the splined output shaft from the 4T65E that the axle slides onto, moves around a lot. It also moves in and out of the housing. It has quite a bit of vertical and lateral play.
Is this normal? I can move it around, even with axle attached in place. I'm still getting a pop sound when shifting from R to D or D to R. I haven't done the other side yet though.
I have no idea why this would move so much, and if something is wrong with it, how do I fix it?
Any help or ideas would be appreciated!

For the most part it just floats. There is a seal on the ends, but that'* on the axle, not the output shaft.

So the anchor point for the inner joint on the axle just flops around? Really?
If its supposed to be under a load (accel, decel,) wouldn't it change the angle of the driveline by twisting up while its trying to turn the whole CV axle out to the hub?

It just makes no sense to me why that should move at all. The inboard joint on the axle allows movement in and out, the point the axle anchors to should only move rotationally. Even with the axle in place and the seal intact, the inboard joint moves up and down, left and right when locked into the output shaft. That can't be normal, can it?

I've replaced just about everything in the front suspension 2-3x over now, and am no closer to solving this vibration. I still have the pass side axle and bearing to do, but if that fails to eliminate the pop and the nasty vibrations I'm getting, idk where else to look. None of the shops I've had look at it have any clue what to do other than throw parts at it and figure it will eventually go away. Its getting ridiculous.

I've taken several 4t65e transmissions apart, the only place the output shaft is held is at the diff. There is some play but without seeing what you have I can't say if it'* more then normal.

Yes..the output shaft is only held to the diff by a clip like the one on the splined side axle. On the driverside, there'* nothing holding the output shaft at all. The holding is achieved by a bearing in the channel plate casing right behind the axle seal that the axle rides in. Same thing on the passenger side, except the bearing is in the diff cover.

Technically it'* the axle that is held, not the output shaft.