My 2004 XKR has always had the "lurch" before coming to a standstill. The transmission TCM was flashed with the latest version which made no difference and I have just completed a fluid change which seems to of made a slight improvement but not a complete cure.

Just out of interest, my neighbours BMW Z4 has the same ZF transmission and his car does exactly the same!

 

Mine was pretty annoying, it was a bump / lurch.
Have never had anything done to my ECM but the fluid and filter change made a pretty big difference. It still has a little lurch but nothing like it was prior to changing the fluid. I suspect it will get even a little better when I dod the fluid again.

 

I am having my 03 XK8 trans fluid changed Monday/next week, ganna have the rear end fluids changed out also. My is not bad at all, I hope it fixes it all together. I don't want to pay to do it twice, yea I am not doing this one myself.

 

I had similar issues on several transmissions. They were covered under different warranties so there were different rituals and solutions.
I agree with initial observation that the problem is less prevalent/observable in "sport" mode.
As luck would have it my sport mode switch is broken (have replacement on hand for about five years) where it doesn't latch down to regular mode dependably, not a lot of difference in mileage, car seems to be generally happier.
The root cause is a different issue, sport mode will mask the problem, not get to the bottom of it. I had original transmission start having this issue as well as a "whoop chirp" noise on downshift which also seemed to be worse in "normal mode" the dealer followed a jaguar ritual with an additive, then when that did not resolve the issue, they did a complete change of fluid and found a cracked plastic fitting that could have let moisture enter the system. This seemed to resolve the issue. Due to friends on this forum, i took the advice to pull a warranty on the transmission - not for this problem but the more subtle "whoop chirp" when down-shifting. That transmission worked pretty well for about 10K more miles and failed as in display on dash "Transmission Failure". Re-conditioned transmission installed by dealer had the same bang when you came to a stop (both times it was worse until car warmed up) they spent several days adjusting settings, re-flashing transmission, etc. and resolved the banging, etc. that transmission failed about 25K miles later. Third time's a charm, another reconditioned transmission, similar issues, similar corrective practices, however, the dealer checked for problem and corrected, prior to turning car back over to me. This one seems to be working well with about 40K miles. Bottom line: I think adjustment has something to do with it, i think moisture intrusion can happen through very small openings and is deadly to these transmissions. when you change fluid or have it changed, look around carefully and check for cracked vent pipes, etc. Good luck, and don't despair, my experience was not typical, however this issue seems to be reasonably typical and solvable with this car.

Kind Regards,
Steven

 

The whoop chirp is another well known issue. It was originally solved with a small bottle of additive then later with a revised formulation of transmission fluid.

Although not all transmissions can be cured of 'the lurch', I understood that the whoop chirp fix was 100% effective.

 

yea when in sport mode the trans issues are not as bad.

 

I bought my Mercon SP here. 5.78 a quart plus shipping. They sell by the 12 bottle case only.

ATF Transmission Fluid Mercon SP, XT-6-QSP, Motorcraft