Is it a transmission issue?

[e70junkie]

Hi E70 community

I recently upgraded my much beloved 2004 E53 30d to a 2011 E70 30d with the 180kw engine. I loved my E53 and have driven it for near 8 years without any major issues. Just the usual maintenance. I loved it but the age and mounting maintenance, plus signs of early diff deterioration have forced me to upgrade. That said, I love almost everything about the E70. Bar two things.

1. The car by default is rather under powered. It actually felt a bit held back. Particularly in the low range where the car would plateau around 60-80kmh then coast till about 100kmh and then the high turbo kicks in for a good result.

2. The proverbial accelerator lag between the time you hit the pedal and when the car actually responds. I sense there are two places where this lag occurs. (2a) First is when you are stationary and want to go, say at lights. (2b) Second is when you're moving but want to accelerate sharply. Say when overtaking or coming out of a round-about or corner uphill.

I did enough research to know that problem (1) can be easily rectified with a ECU tune. I have done this and managed to get the car from a default 180kw/540Nm to 220kw/610Nm. The car is a rocket, especially in sport mode where none of the usual hesitation exists. Car just goes with black dust in the rear vision mirror and a distant view of cars staying far behind. I did this with a HP-F tune which I highly recommend. Horsepower Factory (in Melbourne AUS). So far so good. I love driving my X5 in that configuration.

Problem 2a was also resolved with a accelerator module fitted. Which simply gets installed inline between the pedal and the ECU controlling the throttle. This works relatively well.

Problem 2b, that's another story and is really annoying. My guess (or maybe estimate) is that there is 1-2s maybe even as mush as 3s delay between request (of the driver by pressing on the pedal) and response (the car simply exploding into a mad rush). I like the ultimate response and clearly the car has the power to deliver on the "give me power" ask, but this does not happen straight away. The E53 did not have that problem. It was basically power-on-demand. The E70 is like "you want me to do what? Let me think about it." and then it just explodes into a run-like-a-bat-out-hell acceleration. Just before that happens it feels as if the car is kind of stuck in second gear before the transmission finally figures out what you want to do, drops the gear down by one and delivers the power.
I also noticed this behaviour at higher speed ranges. Where for example, I'm going at say 60-70kmh and want to overtake, press the accelerator, the car thinks about it, and after a delay of 1-2s drops the gear, and off we go.
It makes me wonder if the transmission is permanently stuck if "the gear it should be in plus 1". Is this possible? Can it be fixed? How?

Any thoughts or comments would be very welcome.

cheers
Mike