Have a 2008 CTS 4 w/DI engine. When I'm driving along at cruising speeds and step on the gas to pass or speed up quickly, the front end drops and the engine revs while it waits for the trans. to kick down a couple of gears. The result is a hard downshift and the car lurching forward when it finds the right gear.
The car has been doing this since it was brand new. Dealer says there are no driveability issues and the transmission is operating as designed.
Seems like they are full of it. Any thoughts ? Any TSB's out regarding this type of issue ?
What you are describing is the electronics synchronizing the engine speed to the lower transmission gear. Ask to try a different car at the dealership.
EMC, I wrote about a similar transmission problem in one of the two 08's I test-drove the other day. (See my post "Disappointing Test-Drives".) The salesman acknowledged the transmission behavior was a problem and he was going to take the car into Service while we found another to test-drive. They were both base engine, not sure if that matters. Good luck with yours, I hope you can get it resolved.
If I'm on the highway at cruising speed and floor it, the nose drops as if you
hit the brakes, then a second of nothing (like it may have stalled), then it
slams into 3rd (or whatever gear it chose) and takes off like a shot. If I press 1/2 way it does the same but to a lesser degree.
As I say, dealer said it's operating as designed. Is anyone else's trans. like this ?
No. I have the same set-up: DFI, and AWD. Transmission and shifts are very, very smooth, including flooring it (had to do that yesterday on the Interstate to get around a truck).
I do not get a transmission slam, but I do get a power stall of a few milliseconds duration - just long enough to think that the engine has died before the power kicks in.
At cruising speed it's happened several times when I nearly-floored the accelerator while changing lanes to pass a slower moving vehicle. Very unnerving...especially in the face of oncoming traffic. Dunno, but I assumed that it was caused by the computer-controlled electronic "drive-by-wire" accelerator.
Yes, the one I test-drove also had the power-stall thing -- as I mentioned, it was while slowing down rather than accelerating though. The transmission made a big clunking noise while downshifting, and then a couple times it sort of stalled for a few seconds -- I actually thought I had knocked the shifter into Neutral -- before clunking into the right gear. The next car I test-drove had a very smooth transmission, not at all like the first one even though it was the same model. I agree with the poster above who said to compare it to another car on the dealer's lot.
I think what you describe is normal. My experience is similar – when flooring the gas pedal there is a time delay – how long? I do not know but I did notice it. I believe it is for transmission to downshift. After that car takes off like crazy! Unless you have F1-type gearbox (20 milliseconds to change the gear!) to you have to accept it. Oh, and I do not think manual would be quicker….it is just a perception as you “are busy” making many different things – taking off the foot from accelerator, selecting right gear and pressing gas again – so it seems to be instant. Now that computers control everything car manufacturers are making sure our ignorance does not hurt the car….
you might also see if the delay is lessened if the transmission is in "sport mode". The heavier duty GM automatics used in the HD pickups have a similar delay that disappears when the alternate transmission programming "tow/haul mode" is selected.
I am still giving mine a gentle break-in since it is only a few days old so I won't be experimenting with full-throttle forced downshifts for a few days.
