AWD Transmission: Geartronic goes to neutral

[4wheeldriver]

Mike

The only time mine wont do it is on the motorway above 70mph (71 honest officer) and if I have it in manual. Rest of the time unless I use manual and have it in the red nearly changing down up to roundabouts its at idle all the way. No engine braking feel at all. think its time to look at the BMW website again.............................................

[GSMGuy]

Definately doesn't sound right at all...

I'd be asking the Dealer if you can drive their Demo to see if it's the same..

Mike

[4wheeldriver]

I didnt buy it from the local dealer so theyre about as helpful as an ashtray on a motorbike. Mind you theyre ALWAYS that helpful.............. Ill wait and see what the supplying dealer suggests

[GSMGuy]

Can't understand the local dealer not wanting to help, after all, if it's a warranty job, they get paid by Volvo for doing it, and they may get your servicing etc if you get sood service from them over this...

Dealers should be trying to win and keep custom, not driving it away!

Mike

[4wheeldriver]

Originally Posted by GSMGuy

Can't understand the local dealer not wanting to help, after all, if it's a warranty job, they get paid by Volvo for doing it, and they may get your servicing etc if you get sood service from them over this...

Dealers should be trying to win and keep custom, not driving it away!

Mike

In answer to the above Mike. Have a look at my post for the guy having problems with the cupholder flap and what my local dealer told me. Obviously down your neck of the woods you dont have to suffer the Arnold Clark dealerships but to say that Ive now made FIVE complaints to Volvo UK over the local one here, 2 of which have been in the last two months, I think thatsays it all about them. Ive had alloys kerbed by them, paintwork scratched, 1 "mechanic" blew the turbo on my t4, another broke the agitator ring for the ABS while changing a wheel bearing then I was made to pay for it as when I signed the service instruction sheet I gave them the authority to do it, and it goes on and on. I could fill page upon page with the vrious problems I've had with them hence my dealing with a South England dealership for the xc90. I was speking to a woman in Clarks 2 weeks ago and they changed a brake light bulb for her. How much would you hazard a guess at them charging?? Answers on a post to myself lolol

[4wheeldriver]

Latest update on the saga......................

Selling dealer have admitted theres a fault with the gearbox from the description Ive given them etc and are now contacting Volvo Techncal to find out if they have a cure for it. That was at 12:00 today so we'll see how long it takes for Volvo to to come up with an answer/cure for it!

Ill update more as I hear anything.

Thanks to all for their help and suggestions that Ive had.

Oh and the answer to the brake light bulb was 48 quid and pennies!!!!

[RoyMacDonald]

Originally Posted by GSMGuy

This is actually incorrect - Diesels have far BETTER engine braking than petrols, due mainly to the much higher compression ratio, and to a lesser extent, the greater mass of the rotating components, due to them being heavier.

Vacuum pumps are fitted to a diesel engine in order to power the brake servo, as they do not generate manifold vacuum, due to them being unthrottled.

I know my D5 Geartronic only really has useful engine braking when in Tip mode and 1st or 2nd, as I use it descending the rather steep hill in Wales where my Mother lives - During town driving, when releasing the throttle, the engine tends to drop towards idle, I assume this is because of the fact that the torque converter is operating in "unlocked" mode and that it has been programmed to do so in order to improve low speed driveability, by reducing drivetrain shunt, and to improve emissions and fuel consumption.

Above converter lockup speeds, ie approx 40 in 4th/55 in 5th then the motor speed tends to drop only marginally on lift off, again I presume to improve driveability and due to the locked torque converter.

HTH

Mike

Mike......I went from a 240 petrol to a 940 diesel and the 240 had much better engine braking than the 940. Check out this article which has a bit more info on the subject ......http://en.wikipedia.org/wiki/Jake_brake also.....http://en.wikipedia.org/wiki/Retarde...l_engineering)

Although 4wheeldrive appears to have a fault, I would comment that the gearbox will always appear very different to what it was before the new software as the software is "intelligent" and changes it's behaviour over a period of time to suit the drivers driving style. An upgrade resets the gearbox to it's default settings.

All the best.

Roy

[GSMGuy]

Appreciate what you are saying Roy, those apply to large heavy endines - whereas we are dealing with relatively small high speed engines in modern cars, thats why they don't have exhaust brakes or retarders - engine braking is sufficient. Try turning your diesel engine over by hand compared to a similar sized petrol.....



Mike

[RoyMacDonald]

Originally Posted by GSMGuy

Appreciate what you are saying Roy, but it's still wrong..... try turning a diesel engine over by hand compared to a similar sized petrol.....



Mike

Ohh..... you bought the version with the starting handle Afraid I haven't used a starting handle since the 1926 Rolls Royce I learnt to drive in.

I don't think that's the same as what happens with engine braking though Mike. You are trying to compress a fuel/air mixture when you turn an engine by hand. In diesel engine braking their is a minimal amount of fuel so, to quote Wiki " the accumulated compressed air in the cylinder acts as a 'spring' to drive the piston back down again" Also any small amount of residual fuel remaining will also add momentum to the piston stroke.

Roy

[4wheeldriver]

Ok boys!!! Calm down lolol. Im was an HGV mechanic to trade originally and in the "heavies" there are 3 different types of engine brake. The exhaust brake which turns the engine into a compressor by shutting off the exhaust using a butterfly valve in the down pipe. Too be honest it really doesnt do much other than make lots of noise. the 2nd is the Jake or JAcobs Brake. Most commonly found on Cummins engines. It shuts all the valves of the cylinders down and in later models could select 4, 5 or 6 cylinders depending on the amount of retardation needed!! The latest type are electronic using a magnetic system also used in coaches. They were introduced after I left the trade so Im not au fait with there workings but they are believed to be the most efficient. To the best of my knowledge, none of these systems have ever been used in cars as the swept volumes of the bores aren't large enough to have much effect. in the case of the 1st 2 its a case of the smaller the engine the less effect it has on the speed of the vehicle. The newer magnetic ones I'm lead to believe have a BIG weight penalty so again I dont think they would have been able to aply them to cars. the Jake brake would be about the most effective in the smaller car engine as it involves the least amount of extra weight to braking achieved.

Hope this solves some of the arguments on this score. Either wany it still hasnt sorted by dodgy gearbox!!! lol Oh and its now getting worse. The wipers have now developed a mind of their own and the power steering has half packed up!! Oh and Volvo still havent come up with a cure as of half 3 this afternoon.

In addition to the Jake Brake Volvo Truck and Bus now have What they call the Volvo Engine Brake. Similar in design and VERY effective. Perhaps we should ask for them to be fitted to tow cars. Mind you in my case it wouldnt help lol