transmission lines
 

how to replace lines on a 2001 blazer

Look & take pics where they are, how they're clipped in & to what where, how they're routed. Get OEM lines, new filter & oil, pan to catch old oil & make sure you have the right sized combination wrenches & sockets. Some sort of Sorb-All or kitty litter stuff for oil spills wouldn't be a bad idea either. After loosening the trans pan & draining the oil (great opportunity to change the oil & filter) remove 1 line at a time. If you purchased OEM replacements then they'll be pre bent & should only be able to go in one way.
If you don't want to go through all that then just replace the lines without draining the oil. I'm pretty sure they're above the level of the oil pan. Just check the trans fluid after & top it up as needed.

Have you tried searching in here?

transmission lines
 

do i have to drop the transmission to replace tranny lines on a 2001 blazer