Hey all,
I've got a 2001 S80 T6, and when it's cold and STC is on, the car will seem to "slip" into third gear and continues to do so even after it's warmed up. I turn off STC, and the car seems to gear hunt between 3rd and 4th when driving slowly, but drives like a dream once warmed up. Fluid looks / smells good, and I'm a wee bit stumped with this one...anyone have the slightest idea as to what's going on?

No warning lights for trans codes, abs or stc for that matter.

 

Hi, What ever are the reasons are, bad news is that your tranny is about to expire...exactly it happened with me.....and finally got changed solved the problem.....

MILLION DOLLAR TIP: Never drive car while cold...get it warm then move on....this way you can keep the time not change the tranny....and NEVER EVER THROTTLE THE SPEED while cold engine ..Bcz once the Transmission valve body won't work ...then it will give you the transmission problem code and sign.
Plus
If you never change the oil and filter...then DO NOT DO SO...it might stop your transmission for ever and might need tow.......moreover do not go for rebuild....only change transmission can help and save time.

Good Luck.