Just bought a 2007 XK with 25,000 miles. Love it! But whether in Drive or Sport, when I coast to a stop, or coast down a slight grade, the transmission automatically downshifts through the gears as the car decelerates. Is this normal? I'd prefer it didn't, at least not in Drive (the costing downshifts hurt fuel efficiency). I figured the transmission would leave it in the original gear until I either approached a full stop or touched the accelerator again (like what you do in a manual.)

Come to think of it, I don't like it in Sport either, because it means I'm not in control of gear selection!

Is this normal in everyone's XK?

 

It works that way in every car I've ever driven with an automatic. It's normal. Why do you think it hurts fuel economy?

 

That is not the proper way to drive a manual, either. I hate people who drive that way. Especially when they are trying to drive in a spirited way. Downshift using heel-toe into a proper gear as you slow down!

Then again, this might explain why my fuel economy is so bad on my manual Mustang.

 

Then again, I just test drove a 2009 XKR in sport and drive modes, and it did not appear to exhibit any of the behaviors you were talking about. In drive mode, coming to a stop, the car did downshift but did so very smoothly and kept revs around 1200 rpm or so.

 

Mikey, it hurts fuel economy because when you're in a lower gear your car decelerates faster. My transmissions behavior means I spend longer on the gas before approaching a stop, or not coasting as quickly down an incline that wouldn't call for braking, etc. It also means more wear for the transmission, also a concern. It's very strange.

 

amcdonal, it's not the "spirited" way for sure. But in normal driving it's the most fuel efficient and the easiest on a transmission. It's the way you're taught in driving school (not racing school!) for manual transmissions.

 

I'm wondering if my transmission "learned" this behavior from the previous owner. But she was a tony lady from the Hamptons, not some boy-racer.

 

I can assure you that there will be no additional wear on the transmission- the 'gears' are just as suited for slowing a car through compression as they are for accelerating. This flies in the face of what was taught in school but that was 40 years ago and I'm still waiting for someone's transmission to wear out.

My S-type changes to lower gears as the car slows, readying it for acceleration as soon as I touch the gas, but actual engine braking is negligible. To achieve this, I have to manually select lower gears on the other side of the J-gate.

 

If you are feeling distinct deceleration with each downshift, then it sounds like the torque converter lockup might my acting weird. Either that or the transmission has learned some strange driving habit from a previous owner. Either disconnect the battery for a while or get your dealer to reset it.

That said, the 6-speed ZF does not coast/sail quite like a GM transmission. Even so it is unlikely you are using any extra gas as the overrun fuel cutoff is pretty aggressive on most cars these days.

 

pabanker, now that I actually own an XKR, I can tell you that this behavior is not normal. When coasting to a stop or braking to a stop in "D", the rpms stay at idle--very steadily.