I have been experiencing while in Drive mode rough downshifts while slowing down. It is more pronounced when I am braking under 30 mph. It definitely is not a smooth transition to the lower gears. I have read some threads for other models about transmission surging and I don't know if this is related. Upshifts seem to be fine. I have it at the dealer now for this very problem, but of course for the service manager it behaved. He said they would check the files and fluid. Anyone else experience this harsh downshifting while slowing down?

 

...that sounds like a torque converter issue... but if so, the inability to reproduce the issue is really odd.

Moving to a high-stall converter in a drag-oriented car can produce this type of behavior.

Good luck; please update us when resolved!


Rich

 

Do you use a battery maintainer? It's possible it's an electrical gremlin.

Otherwise, you may want to have the TCM adaptations cleared/reset. This symptom seems to be very common on S-Types and X350s, but I haven't heard too much about it for X150s!

 

Yes, it is fully charged every night with my CTEK 3300. The service manager was super conservative with the drive with no hard braking or acceleration. I should have driven it as I know how to reproduce it. It's hard to think of transmission issues with 5,800 miles. I told the service writer to take their time because the condition is there, regardless of the test drive. I have less than a month left on the factory warranty and then will be going to an extended warranty with Easy Care/Total Care. Wouldn't service know to have the TCM adaptations cleared or reset if it is symptomatic without me saying anything? Is this the same as an adaptive transmission reset?

 

I may not have described the shifting symptoms correctly. My car does not bang hard when it downshifts to a lower gear. The best description would be imagine you were driving a manual shift car. You are slowing down with the brake and letting the clutch out at the same time, causing the engine to rev up high. It feels like a clutch engaging but not smoothly. I've felt this with the PDK (automatic) transmission on the New Porsche Cayman in sport mode but that is characteristic to those double clutch transmissions. Also, my transmission does not do it all the time.

 

My car did that when the battery was low. I'd have them do a load test on your battery just to make sure. Mine would downshift on it's own while slowing down like you shifted down a gear. Once I replaced the battery, that went away. It would also do this in Sport Mode but I don't remember if it was during the low battery incident or not.

 

I had a load test done on my battery last week and it is fine as well as the alternator. Once I pick up my car from the dealer I will report back.

 

I got the car back from Jaguar. The shop manager told me that although he didn't find any issues, he had the TCM adaptations cleared and the car does seem to drive without the harsher downshifts. I was told to go easy for a few hundred miles and not to use Sport Mode which I don't use anyway. The manager said that if I had an internal problem it would be evident even with the adaptive transmission reset. I'll see how it goes for the next few hundred miles and report back. I have my fingers crossed and am cautiously optimistic.

 

Interested to hear your findings. My car (08 XKR) did this once recently, same symptoms as you describe - like downshifting in a manual without matching the revs as you let the clutch out. I found once I'd stopped and started the engine again it was fine. Was yours doing it all the time?

 

Mine was intermittent as well.

 

UPDATE.....After a few hundred miles, my car's downshifts are still noticeable. If I let the car slow down on it's own from 30-40 mph, I can feel the car downshifting to the lower gears. As mentioned earlier, upshifts are all smooth. I had a 2014 XF as a loaner with 2,000 miles, and although it was not as noticeable I was aware of the car downshifting when slowing down. The service manager did say that being able to feel the downshifts was characteristic of the ZF transmissions.

 

Can you not test drive a few and compare?

 

Change the transmission fluid and filter. Do the usual sump drop and fill. And then a couple of fluid changes over 200 odd miles.

That will sort it out.

If that fails your valve body needs an overhaul.

 

I am not sure I am missing something, I can "feel" downshifts in both my XF and XK. If I am in "S" mode th shifts are more noticeable as the transmission seems to try to keep the revs above 2,000rpm. In auto it just seems to downshift just around 800-1,000rpm, maybe not always noticeable but I can definitely see it on the tach.

 

Yes, if you are feeling the downshifts, this is what I am experiencing. It is just a matter of how noticeable it is or how harsh. Mine is sometimes not noticeable at all while other times feels as if the brakes are being applied as the car slows down. I know other manufacturers other than BMW having automatics with unnoticeable downshifting when slowing down. The S mode is a different animal and is normal and expected to feel the more pronounced shifting. I didn't expect this in Drive mode. If you do any search on either Thelurch.com or just lurching with earlier Jaguars, you will have enough reading material to keep you busy for a lifetime. X150s supposedly do not have as many issues, but some have been reported. It seems to be a software problem that some owners experience while others don't.

 

I test drove a 2011 XK yesterday with 6600 miles on the clock to make a comparison to my car's shifting pattern. I was definitely able to feel the car downshifting as it was slowing down. It is a characteristic of the ZF transmission both in the XF and XK. I guess some owners either don't notice it or have become used to it.

 

I think you hit the nail on the head. It is just something you have to get used to. My old X350 felt about the same as my X150 in automatic mode. I know people with X-Types and S-Types (and X350s) have had their issue progress worse to a lurch that felt like they were getting rear-ended as the transmissions shifted into 1st coming to a stop.

One solution is to aggressively downshift using the paddle shifters as you come to a stop. At least then you'll be expecting the lurching, and it will sound cool!

 

I feel a downshift when slowing in my 2012 xk vert. I would not call it abrupt and it kicks in at about 1k 1.2k rpm

 

Bingo! I might very well have incorrectly described the downshifting as "abrupt", but coming from a Japanese car where there was absolutely no evidence or awareness of when my car actually downshifted to lower gears, to me my XK seemed "abrupt" when in actuality it is the normal sequence and characteristic in our ZF transmissions. Since I have been describing it, the handful of members who are scrutinizing their XKs downshifting behavior in Drive are becoming aware it can be felt.

 

Most newer cars transmissions do this. It is to assist with slowing down. It is slight engine braking. It is totally normal. The reason you feel the downshift is because it is down shifting and reaching a higher rpm to assist with braking. My gf has a 2011 honda with the V6 and you can feel it downshift as well and that car stops on a dime. I noticed that the first time I drove it.