i figured since i dont have the car any more, its safe to ask and not worry myself. there were many occasions when I would lift off the gas and coast, and the transmission would make a roll and knock noise, like a clunk and downshift. I could have sworn it was normal and i experienced it in my 2009 XF i once had as well.

 

I've been experiencing that myself more often lately. The transmission mount is fairly new, so I'm wondering if its the engine mounts or the flex joints in the driveshaft.

 

My understanding this is the known Jaguar ZF sourced ZF6HP condition where the car jerks when coming to a stop as it shifts down gears automatically. I noticed this on my 2012 which was the last ZF6HP model and I had updated to new TCM software to help with the jerking.

As my car got older, now the shifts are not always as smooth. Especially when cold I expect it to happen more often. After driving the car hard and warming the transmission oil up the car drives smoother and less of that jerky shifting. I do hear a noise when it does the shift kind of like a clunk but it doesn't sound too bad.

Not really sure of the roll and knock noise...mine just sounds like a click/clunk type noise. Sometimes its hard to explain nosies over text though lol. I still think these transmissions are one of the best since ZF have been making the 6HP for so long. My car still shifts very fast using padels which is great for a 2012 and below car. My car shifts as fast if not faster than the new Kia Stinger which i test drove - they have their own KIA transmission which is decent and more gears.

 

I had similar symptoms on my 2010 XJ with the same transmission. Replacement of all mounts made it 90% better. There is no more sound when I apply or lift my foot off the accelerator anymore (particularly around 1500rpm). There is still a very quiet clunk every now and then when I put the gear selector into park. It used to be a very loud clunk.

The shifting is much better but still not perfect. Pretty sure changing the flex joint will bring it to 100%.