Transmission delayed when shifting into drive, should I be concerned?

[jacintocollier]

Lately my 318i has been taking a second or two longer than usual to engage when I shift from park into drive, especially on cold mornings. It's not a huge delay but it's definitely not as instant as it used to be, and I've convinced myself it's the start of something expensive. A mate at work told me to check out this page after I mentioned it to him, saying they explain the common causes pretty clearly without all the jargon. I haven't booked anything yet because I'm hoping someone here can tell me if this is just normal wear or if I'm right to be worried. Has anyone dealt with a similar delay? Did it turn out to be fluid related or something more serious? I'd rather hear from people who've been through it than guess and stress about it every morning.