yes the rear main shock is done on your sled. the 04-05 rx warrior/rage had a non rebuildable shock in them from factory. odds are the other 3 need to be serviced as well as they do degrade over time.
@cannondale27 does most of my shocks. there are a few good guys here in ontario as well.
there are 4 options, find a good used one
find an olins for it
convert it to use a rx1/sx viper shock that is rebuildable
install a hygear replacement one.
used oe, do not think there are any good ones left.
olins quit making them when pioneer suspension closed as i got my set for my 05 pre 2010.
rx 1/sx viper shock needs the relay rods beside the shock as well and middle mount needs to move closer to back one as the stock warrior shock is longer by over 1/2" and it messes up geometry/ride if you do not.
I just discovered the hygear one in the last year, witch is a direct bolt in for oe.
https://www.hygearsuspension.com/en...warrior-rs-vector-rs-rage?variant=29472454531
brothers 04 was due at 20000 km and i could feel the diference in my 05 switching out with him before i put the olins on it.