[sjlucky]

Wanted to see if anybody else has experienced this before...

my street has a relatively high incline getting out on to the main road. I usually let the car warm up for a minute or so (at least the rpms go under 1k) before driving it in the morning. I find that once I get up the hill...stop...and then start again...there are times when the transmission would jerk the car shifting. When the car is warm...it's smooth as butter. But it seems like it's really just a matter of warming things up.

I don't slam on the gas or anything...normal driving. Just wondering whether there's anything with the computer that changes the transmission shifting points (perhaps due to the incline) or perhaps just the colder start in the morning that may be causing this issue.

Doesn't happen all the time but it does once in a while. Any insight would be appreciated.

 

[umbertob]

Yup, that's "normal" behavior of our ZF 6HP26 tranny, it won't upshift from first gear until very high engine revs when driven uphill with a cold engine, causing the "jerk" you notice as you touch the gas pedal... Symptom disappears when the engine warms up. Something about the transmission "Gradient Mode Strategy" (don't ask...), supposedly corrected on MY08s and later. It's documented on the ZF's troubleshooting guide uploaded here: download/file.php?id=1415

I also live on a fairly steep hill and experience that same occasional jerk and hesitation at times, as I leave my house with a cold engine in the morning and drive uphill. No worries. :thumb: