Hello. Below is a very accurate tab (probably the most accurate you'll ever encounter for the song) along with the isolated bass for this recording. Have fun!
(I'll explain more about these files in case you're interested: The song was included in the game RockBand 3 as downloadable content. That is where the multitracks for this song leaked from. The song was released as a "Pro Mode" song, which means it had real guitar and real bass notation and you could use a "real" Squier Stratocaster (a special midi model sold separately) to play those in game. I play a different game called Rocksmith, which is similar except that you can only use real guitars and basses. I make custom songs for this Rocksmith, and sometimes use the files from RockBand to do it. I recently made this song using the 'tabs' from RockBand. Those bass tabs tend to be just about perfect because the charters who made them were listening to just the isolated bass recording when they made it (unlike the pro transcribers for Hal Leonard, who have a much more difficult job listening to CDs and transcribing like the rest of us). I have included a PDF of the GuitarPro file that I made for use with Rocksmith and the isolated bass recording of Geddy Lee from the RockBand 3 game. I apologize for all the tempo indications in my PDF. That's a side effect of having to properly synchronize the notes to the original recording. The usual "chorus, verse" etc are also missing and replaced with seemingly random "riff" labels instead due to the needs of Rocksmith. But it does accurately represent what Mr Lee played note-for-note. Check my signature if you want to learn more about the several thousand isolated bass recordings we have access to thanks to GuitarHero and RockBand.)
P.S., If you are doing Rush songs by ear and would like the isolated bass for certain songs, PM me with their names and I'll get them to you if I have 'em.