Aw11 wobbles

[thegreatestben]

My red adub is still getting a wobble on when I change down gears at highway speeds.
I know it's not alignment or wheels or tires. I've checked everything is tight in the way of mounts and suspension. My thoughts are that it's because I slammed a new bellhousing on the gearbox without any sort of correct method in checking the diff is correctly shimmed.

Would this cause issues like I'm having?