What entails in a transmission swap?
 

I'm saying replacing a 4L80E with an NV4500, or maybe even an NV5600 in a 1998 Silverado 4x4. I know theres some computer/reflash needed for the engine. But would it be a bastard or not too bad? My 4L80E is okay, I'm just really bias to the manual. And what manual shift transfer-case would work well with the NV? I have push button and... well, I'd feel better with the manual case. Thanks for any info.