Just wanted to see if anyone has any input on this.
In the morning or after the car sits for a couple of hours for the first 30ft or so the car makes a rotational hum from the rear end.

I don’t have any play in the wheel bearings and the prop shaft is brand new as of 15k miles ago.

My next bet is to take off axles and check them and the rear end for play in the bearings, I don’t think that’s a common failure point on these though.


Car is a 2002/3 2.5 5spd with 150k miles.

 

Mine has what I would call a fluttering hum when starting out in the morning. It starts at maybe 20 or 30 seconds into my drive and lasts about 5 seconds. It has done this for at least the 8 years I have owned the car. I have learned to like the sound.

 

I'd do a diff-oil change... - good idea anyway and you might be low on diff-oil:

https://www.jaguarforums.com/forum/x...change-273829/

 

Brand new fluid in the rear differential already :P.

I think I’ll ignore it until I get my motor mounts swapped so I can make sure it isn’t somehow related to those.

 

Who did the diff-oil change and did they know, what they were doing?
Did they fill in sufficient diff-oil?
What kind of oil exactly did they put in?
If someone did a stuff-up there, "waiting" is not option No. 1...

 

So I have had something similar for pretty much the entire 3 years that I've owned my x- – type. It's very weird to describe, but your description of rotational home sort of fits it. I got an alignment after I did some suspension work and that seemed to make it a lot better but not go away completely. This is one of a few things on my Jag that is easily fixed by the radio. Just turn it on and turn it up, problem solved 😂. I'm not even joking. It's been 3 years. No major changes. It's always the same. Comes and goes. I went through it with a fine tooth comb and no answer so it's literally just a quirk. Not because of this sound but because I needed to do it anyway. I changed all of my suspension all the way around except for the springs and it didn't make any difference.