# Bentley GT transmission problems



## retired2play (Jan 30, 2006)

Recently purchased 2004 GT. When slowing to a stop (2nd to 1st) the trans makes a uncomfortable jump as if someone hit me from the rear. Dealer says Bentley can't fix this problem which is also occuring on 2005.
After 30 minutes, the electronics turn off the phone which then can only be turned on manually.
Anyone have problems like this? 
Retired2play


----------



## A64.2wasme (Jul 15, 2003)

*Re: Bentley GT transmission problems (retired2play)*

Re: the transmission problem: My '04 A8L did the same thing, and I know from the AudiWorld D3A8 board that others have noticed it as well. I don't know if it happens on later Audis. I haven't noticed it on the Spur.


----------



## Dave_1966 (Feb 19, 2006)

*Re: Bentley GT transmission problems (retired2play)*

Ask the dealer to reset the adaptive settings - They have a process they can drive the vehicle to improve the problem.
Dont know about the other problem though


----------



## PanEuropean (Nov 3, 2001)

*Re: Bentley GT transmission problems (retired2play)*

Dave is correct in his recommendation. To reset the transmission 'learned behaviour', all the tech has to do is enter a value of 0 (zero) in adaptation channel 00 of the transmission controller - controller 02. That should do the job for you.
At the same time, it would make sense to have the tech check the ATF fluid level, if it is overfilled or underfilled this will result in poor shifts. The fluid has to be at a very specific temperature to be checked (+35°C), and it can take quite a while for it to cool down to this temperature if you have been driving the car recently. Best to drop the car off at the dealer the night before, and pick it up the following day - this ensures that the transmission can cool down and the measurement can be made with precision.
Michael


----------



## retired2play (Jan 30, 2006)

*Re: Bentley GT transmission problems (PanEuropean)*

Thanks, Michael for your input. I have now experienced a decrease in the rough shifting as it occurs only every so often. The dealer explained this change is do to the system learning my driving habits. Not sure that makes sense but it is getting better. I will take your message to the dealer and see if they can perform the procedure. http://****************.com/smile/emthup.gif


----------



## retired2play (Jan 30, 2006)

*Re: Bentley GT transmission problems (Dave_1966)*

Thanks for you input. The dealer did try this procedure and it seemed to help somewhat, however, as in my note to Michael, it is improving over time.


----------



## Dave_1966 (Feb 19, 2006)

*Re: Bentley GT transmission problems (retired2play)*

Bentley dealers cannot flatten the adaptive values on CGT models.
Only Audi have this option on the new generation transmissions.
The transmission will adapt to your driving style as you continue to drive the car.


----------



## PanEuropean (Nov 3, 2001)

*Re: Bentley GT transmission problems (Dave_1966)*


_Quote, originally posted by *Dave_1966* »_Bentley dealers cannot flatten the adaptive values on CGT models.

That seems - uh - odd, because *ANY *Volkswagen group controller for *ANY *system can be reset to factory default values by entering a zero in adaptation channel 00 of the controller, and saving it. This is basic to the design of all the controllers, because it allows technicians to return the controllers to a known state if they need to do that when troubleshooting. It is very similar to rebooting a computer.
Be aware that you cannot make any coding or adaptation changes to a transmission controller (on any car) if the engine is running. You need to have terminal 15 power present (ignition circuit power), but the engine must not be running. This is a safety feature, to prevent unwanted changes from being made while the vehicle is being driven. Engine controllers have a similar, but less strict condition: Changes can be made when the engine is running, but only when the vehicle speed is zero. 
Michael
Michael


----------



## Dave_1966 (Feb 19, 2006)

*Re: Bentley GT transmission problems (PanEuropean)*

The current hardware in the transmission doies not allow VAS to reset the adaptive values. 
The only way currently is to use an AZG tool as used by the transmission manufacturer.
By trying to carry out this procedure with the VAS5052/1 the screen appears to reset the values, however, it does not make any changes whatsoever. From 07MY, Bentley are going to use a new generation hardware which will allow VAS to perform this function correctly. 
Only in rare circumstances do the adaptive values need to be reset, the dealer have a fast adapt process they can follw to force the transmission to learn new values. In adition to this, as you know, the transmission continues to learn as the driver is driving the car once the transmission has reached normal operating temperature.
Hope this clarifies the position once and for all.


----------



## PanEuropean (Nov 3, 2001)

*Re: Bentley GT transmission problems (Dave_1966)*

Dave, thank you very much for posting the additional information and explaining it so well. I defer to your knowledge of the vehicle.
Thanks,
Michael


----------



## PanEuropean (Nov 3, 2001)

*Re: Bentley GT transmission problems (retired2play)*

Gerald:
Just some additional information for you about the process of checking the fluid level in the transmission.
I own a VW that has the 12 cylinder engine in it. The transmission is not the same on the Bentley and the Phaeton, but, I think it is similar. To check the transmission fluid level on the Phaeton, the car needs to be started, then lifted up whilst running, then the temperature of the fluid carefully monitored with a diagnostic scan tool until it is between 35°C and 45°C. As soon as the temperature passes 35°C, the technician removes the bolt from the pan, and begins to add fluid until it spills out. This process must be completed before the transmission fluid reaches 45°C.
I had the opportunity to watch the whole process being done when my Phaeton was in for service a few weeks ago, it is a bit like a team of chefs orchestrating a dinner... one technician operates the diagnostic scan tool, another takes the bolt out, and yet a third stands on a ladder with a container of ATF and a 6 foot hose, to feed the fluid (via gravity) into the filling hole.
It kind of makes one long for the old days when life was simple and the transmission had a dipstick.








Michael
*Transmission Fluid Checking Procedure - Phaeton with ZF Transmission*
*Transmission Pan Cover - 5 speed transmission*
The exterior of the pan was washed before the photo was taken - the liquid visible on the pan and the exhaust pipes is cleaning solvent residue.

*Steps involved in checking the fluid level*


----------

