My 2010 Premium has started exhibiting a rather concerning behaviour.

1. When coming to a stop there is a distinct thump as the car downshifts, which can be quite disconcerting.

2. Travelling at normal speeds up a hill, say, lift the throttle (such as when someone pulls in front of you going more slowly) and then reapply to get extra urge once they speedup, the downshift can be violent. A distinct thump as the car drops into a lower gear.

It seems to downshift normally when simply applying the accelerator for more power, it only appears to happen after a trailing throttle. Has anybody else experienced this? The car has 30,000 miles, approx.

I am booking it into the dealer asap. but would welcome any comments from someone else who has experienced this.

 

I have a 2010 XFR, and it is doing the EXACT same things....please post what the dealer tells you.

 

In all likelihood it will require a software update to the TCM. I have had similar problems with my X350 (an XJ6 Sport)

 

The interesting thing is that the car has been fine for the first couple of years or so of ownership. So why the change? Wouldn't the problem have manifested itself from day 1 if it was a software fault? I will post when I hear what the dealer has to say.

 

The ZF transmission is adaptive. It is possible you have unintentionally adapted the software unacceptably to you. If so the dealer can reset the ECU to factory default and you can try again.

This transmission suffers from a known issue which ZF claims to be normal. The lock up clutch sometimes gives a little thump when you coast for a short while, especially just as you roll to a stop or near stop. The software is very clever but not as good as an expert driver using a normal clutch.

The ZF also uses the lock up clutch on throttle lift and during cornering to hold the gear and give some engine braking. The more aggressively you drive the more noticeable this effect is. The transmission is waiting for you to get back on the gas before it unlocks the clutch and select a fresh ratio.

 

Waiting until after US Thanksgiving to get the car into the dealership, meanwhile the problem seems to have receded somewhat. Whereas I could provoke it with no real effort, I now find that is seems to have stopped almost entirely. My wife had noted its behavior and she also noted that in the last couple of days it seems to have stopped doing it.

Jagular may have a point that it is a flaw in the adaptive gearbox firmware and that is has "adapted" itself out of the problem. It could also be a temporary blockage in the hydraulic subsystems. Who knows, but it is going to make the visit to the dealership more awkward. I am hoping the "black box" that records engine behavior will help here.... or not.

We had a BMW 5 series that once gave us an error message (in German since we lived in Germany at the time and had a German version of the car) that indicated a gearbox fault. When we called BMW on their emergency number, they told us the gearbox firmware had run out of memory for the adaptive algorithms and that a simple restart would clear the memory and the fault would clear itself. It did and everything worked as it should. Since then we have always been slightly suspicious of adaptive gearbox software