Not sure if I've got a transmission gremlin or not. When I back out of my driveway in the morning, I immediately start down a steep hill about half a city block long. While coasting down the hill and lightly riding the brakes, I've noticed that the ZF on my 06 S stays in low gear and spools the tach up to about 2-2.5K until I hit flat ground and get on the gas a bit. Other than that, the tranny seems to work perfect. Anybody else run into this - Is it designed to operate this way??

Regards:
Oldengineer

 

Sound like the car is compression braking (engine braking).. pretty normal when a car thinks that its going down hill.. Its actually a good thing, not a problem. It saves your brakes from getting hot, especially on extended downhill driving.. Big diesel trucks actually have exhaust brakes to help with compression braking.. My Dad's Ram 3500 came with it as an option. Eric

 

Yup sounds normal to me... But I'm "just a newbee". Eric is right, I notice a lot more engine braking with this car than any other auto I've driven. Another thing it may be related to is I notice that the trans will hold gears (like in sport mode) longer when it's cold in order to help bring everything up to temp. I do get the "lurch" in stop and go traffic so I'm going to insist that my dealer does the flash. My dealer has been great so far so I'm sure they won't have a problem just doing it. BTW it is certified.

 

Does your car perform the same way when you leave your driveway again 20 minutes after you just returned home? In other words, does the transmission performance in this scenario differ when the fluid is up to temperature as opposed to cold?

My wife's 2004 Lexus RX330 is a sluggish turtle when it first leaves the driveway in the morning. Once the fluid gets up to temperature after a couple of miles or so, shift points are fine. Lexus says that it is designed this way. Her previous 2000 RX300 behaved the same way....

 

I believe the behavior is completely normal. I seem to have recalled in some Jaguar literature that the ZF transmission has an incline sensor that would hold lower gears during down hill decents. Furthermore, the tranmsmission ECU is also tied into the steering angle so it will hold lower gears when breaking into turns for improved acceleration out of the turn.

Both features are pretty noticable in my 04 StypeR, but then, I am still learing how to drive an automatic.

 

Yeah its funny you say that because I'm trying to figure out this automatic as well.. I'm used to downshifting into turns and powershifting out of them with my 6 speed.. But now you have to try to predict what the transmission is going to do and I find it muchh more difficult..

 

I haven't decided if the non-predictability is due to the auto with so many gears or the adaptive part since I never had the same issues with older high-performance V8 with 4 speeds. My main issue is 95% of the time, the Jag runs errands with the kids on the weekend (which is why I have this car) and 5% of the time I try to have some fun with it. It doesn't like to have two modes of driving and the shifting pattern constantly changes (down shift point and rate of acceleration vs accelerator position during the transition). Rather have the transmission do the same thing every time and I'll adjust my driving pattern around it...but that may be old school thinking.

 

You guys are right - except for one thing. It apparently is programmed to do this when the temp sensor says its cold outside. This morning it was warm here - I backed the Jag out as usual, noticed the little snowflake on the dash wasn't lit, and she quickly upshifted as I coasted down the hill . Apparently the red beast knows when it's going down a big hill real slow and its cold, that there might be ice. Appreciate all the info - I'll quit worrying about it.

Regards:
Oldengineer

 

Snowflake on the dash?...cool to learn something new everyday. I think my red beast hasn't seen anything below 50.

 

Our dashboard snowflake illuminates when the outside temperature is below about 39 or 40 degrees. Wonder how much variation there is from car to car and geographic location to geographic location on this?

I'll have to pay more attention to cold fluid shifts vs. warm fluid shifts in our S-Type since winter is now nearing its end here in central North Carolina. Thus far, I haven't noticed any shift issues at all. But I haven't had access to the car in nearly two weeks since my wife took it to Florida to visit her elderly parents....

 

The cold temp warning goes on at 39 F no matter what. I laughed at that when I saw it. I found myself talking to my car. "Yes car, I know it's cold outside, that's why I have a coat on!"

 

just so you know, my mazda 6 v6 w/ 6speed auto. does exactly the same thing. I think it is the transmission working correctly.