My T40 has a BG2200 wifi card, which is absolute junk.
It is not a junk for me, or at least not a junk in the option to pick (2200BG or 2915ABG) as 2915ABG is more junk.
It disconnects constantly (probably due to interference) even if I am sitting 5 feet away from my router. I have read that this card is junk anyway.
Seems like a driver issue to me. I had that exact same issue when I used Windows XP driver in Windows 7! Problem solved with a Windows Vista driver and that Vista driver still works flawless to me in Windows 10! In fact I am typing this on a T43p frankenpad (but without SATA mod) with that card in Windows 10! If still disconnects from time to time, I suggest you to take out the card, clean out the contacts and then pop it back in, that fixed the disconnection issue for my mom's X220i!
At any rate, what I am looking for is either an N card, or better yet, a dual band card. Will just about any card fit and work in my T40 ?? I have already performed the No-1802 BIOS hack. Recommendations would be appreciated. Much thanks in advance.
Back to the topic, AFAIK most of the Atheros based miniPCI WLAN card will work with this machine as long as the BIOS mod is performed (which you already did).