Was hoping the excellent folks on this forum could help me with a problem I'm having with my 2010 XF.

My home is on the top of a fairly steep hill and when the engine is cold the car will not shift out of first gear going downhill. I tried the manual shift mode and it still will not shift. If I leave from work where the streets are flat and the car is cold, it shifts ok but still revs too high in each gear.

Question: Is there a sensor that determines the car is at a decline?

Any suggestions?

 

Put it in neutral till you get down the hill.

 

When you described the problem to the dealer did they say "no problem found" because you're describing normal, intended operation....or did they say it *isn't* normal intended operation but they were unable to reproduce the problem for testing and diagnosis?

I'm not really familiar with this model so take this on a "FWIW" basis.

It's not unusal for modern transmissions to be programmed to hold lower gears longer when cold. It's also not unusual for modern cars to have a gradient braking system to hold lower gears for engine braking downhill. Basically, I think the system looks for increasing vehicle speed with closed throttle...and assumes you're going down hill.

I don't really know if either of the above applies to your car. Someone who knows what they're talking about will chime in. I'll shuddup :-)

Cheers
DD

 

What do you mean by "revs too high"? Do you have a number? The redline is around 6,000 rpm, is that what you mean?

I know the transmission will not shift if the chosen gear is too low or too high, regardless of driver input.

I also know that the transmission will assume you want engine braking if you lift off the gas pedal abruptly, the ZF 6 spd does not upshift when you lift off unless it "senses" you have reached cruising speed.

I also know that the ZF will not upshift if a traction control event is detected or the car is in a bend.

If the road speed is suitable for the selected gear ratio then the transmission should upshift if the paddle is activated.

As far as I know there is no hill descent mode for the Jaguar version of this transmission. The Range Rover and Land Rover do have this software. Maybe Jaguar gave you a Range Rover tranny by mistake....8-)

 

Do you have winter mode switched on? Do you have DSC on "Trak"? I'm assuming you have winter tires on. I'm assuming that the weather is on or below 32F.

My understanding is that the XF's gearbox knows it is on a slope so you do get engine braking going down a hill. If you have winter mode switched on it may well be doubly cautious.

if the weather is cold and you're driving off without warming up the car (the correct way to do it) it may also be holding the engine in a low gear until the cats warm up.

 

The dealer said they could not recreate the problem and agreed it was notmal operation. They held the car overnight with temps in the 10-15F degree range and drove the car down hill and said it shifted fine. The hill they selected was probable half the grade as the one I live on.

The car will stay in first gear and rev to over 4500 RPM's without shifting into 2nd. If I stop, place it in park then in drive it will shift from 1st to 2nd but will rev in 2nd to over 4500 rpm's and not shift into third.

Strange....

 

Good questions. I just checked and DSC is off. No winter tires, they are stock and the temp was below 32F. I will try winter mode and see if it makes the problem worse. Thanks for the suggestion!

 

Are you sure DSC is "off"? You need to select and hold the DSC button for at least 11 seconds and until you hear the "ding" or you are only in TRAC mode.

To retain "Winter" setting with DSC "off" you need to select "winter" first and then turn off the DSC, otherwise, selecting "winter" with DSC "off" will switch the DSC back on.

If your hill is steep enough and slippery enough to cause wheel slip with DSC or TRAC "on" then the transmission should not shift as it is programmed not to shift if that might upset the car's balance or traction. If DSC and "winter" are both "off" (really "off') then this gear holding ought not to occur I should have thought.