Dear all,

Real pleasure to be part of the community. I am exploring a Bentley GTC 2008 which has done 92K KM and is in good condition.

There is one issue with the tranmission that in Sport mode, it does not shift to sixth gear i.e. doesnt go beyond S5 even at higher speed like 140 KM/HR with higher RPM like 3K and above.

However, in D mode the shifting is smooth as well as in tiptronic and paddle shift.

Any insights or advice would be highly appreciated to make my decision and apologies if I come as too direct to ask this question.

Regards
Khurram

 

Hello @Khurram98 ,
Welcome to 6speedonline !

As to your issue, do you have a scan tool like Ross-Tech VCDS or ODIS VAS 5054 to scan the transmission, address (02) ?

Also, while in (S) sport mode, if you tap the shifter paddles, does it shift up and down, can you get to 6th gear in sport mode with the paddle ?

Johnny

 

Thanks for your response Johnny.

No I dont have the tool you mentioned. However, I took the vehicle to a transmission expert (Dexol) in Dubai and their technician drove the car.

He actually showed me doing exactly what you just enquired i.e. maunally shifting the 6th gear from the paddle shift as the gear didn't shift automatically to S6 in Sport.

In the D mode, the gears shifted smoothly (D6 came easily even at 90 KM/HR vs S6 not coming even at 140 KM/HR).

The expert from Dexol mentioned this is not transmission issue rather a communication faukt with computer.

Hope that answers your question.

 

Fist off I would do a transmition oil change and add a oil stabiliser
Does it clunk Into gear coming to a stop?
After a while the binocular seal and the actuator tips go hard and let pressure by and need replacing. Mine is the same and will actually lock 5 and 6 together if I'm driving it hard. The valve body needs to be dropped and is a fairly easy fix for a decent transmition shop or garage to do

 

Thanks for your response.

I didn't observe any clunking sound from the gears while the car came to a stop.

Changing transmission oil was also suggested by the transmission expert from Dexol.

The Dexol suggested to take the car to the agency which woukd definitely be a costly proposition.

Coukd this be a major issue with transmission though oyjet than this issue the drive amd gear shift is smooth in D mode.

 

I don't think there is anything wrong with the transmission. Many cars, when in sport mode do not change into top gear which is normally an overdrive gear. Why would you want 6th gear when in sport mode anyway? If it shifts to 6th when in normal mode, then there is no issue with the transmission. FYI, I have the later car with the 8 speed trans so I cant confirm my opinion but many others here can.

 

First off find a garage with a vag com or vas diagnostic they can look into your gearbox, I have a friend of a workmate who rebuilds these gearboxes and he said they are pretty solid boxes but the valve body actuator seals are normally the main cause of issues. An oil change is a fairly easy job for any shop to do but make sure they put in an oil stabiliser as I was told the oil companies are not putting it in any longer and this causes different issue.
First port of call definitely diagnostic

 

Hello @Khurram98 ,
I was thinking about you last night and the supposedly issue that you think you may have, I went to the scanning right of way as you called it an issue, so I took my GT out last night, and after the drive last night, and reading @MUFC 's comment this morning, I agree with MUFC and I believe that you have no issue at all, I would not be jumping to oil change and seals, I would ask others here (with the 6 speed) if they are willing to test the same scenario that you describe, as far as the "Dexol expert" suggesting an oil change also, maybe he/she should know the behavior of the transmission before wasting your time and money...

My 05 GT, which I have the drive train from a 2011 Supersports installed in, meaning the complete engine, engine ECU'S, transmission (6HP-28), instrument cluster, etc., does exactly as you describe, I put it in sport mode and was at 115 MPH / 185 KPH over 3500 RPM and still in 5th gear, I could use the paddle shifter to put it into 6th gear, and it did go into 6th, but as I slowed to 105 MPH / 169 KPH it would drop back to 5th gear on it's own, I believe 6th gear in sport mode comes in automatically at a much higher speed and RPM, I recall being at 186 MPH / 300 KPH in sport mode in 6th gear before, but that was in the wee hours of the morning on a lonely highway, last night's road conditions (traffic, and time of day) did not allow me to me to test any higher speeds, for the safety and respect of other drivers.

Being that you stated that the transmission shifts smoothly, and you have no clunking, I say you are just fine.

Johnny

 

My 08 gt speed is the same. No 6th in sport mode.
Seems to be a concensus that you don't have a problem 🙂