trans dosen't shift when car is cold I have to warm up at list 5min any idea? on 2003 BMW 325i

I have a 325i 2003 bmw .transmission Does not shift from 1-2 until 3500-4000 rpm when cold (during initial take off from setting overnight or at work all day). Works fine once car has been driven couple of miles.Any ideas?

2 answers 3 comments
check your trans fluid first
I DID AND FLUID IT'S OK.
poss trans service, how many miles on car and have you had tras serviced b4
NEVER TRANS SERVICE, 144K
that may help i would start there but have trans codes ck'd 1st to see if there are any