Well today I just picked up a 4l80e from my buddy for $100 and it has the gm goodwrench sticker on the top which tells me it has been rebuilt, I got this for my 06 cc turbo 5.3. But what I was wondering, is this transmission is for the older vortecs without the top bolt hole so why doesn't the 5.3 have the hole tapped under the passenger head or can I tapp it and have any of you guys rebuilt these trans at home I am thinking swapping out the first two gears for the lower tci ones!