Hi-
I assume that just being able to access the solenoid w/o removing the starter is next to impossible (like on my 300d). That being said you will need to pull the starter that has the solenoid mounted to it to take it off- but why bother? Assume that the starter & solenoid are of the same age and if one needs to be hit to work it's probably a good idea to replace both components. While doing the starter removal/installation it's a good idea to make sure your engine-to-body ground straps are clean and tight.
Good Luck!
Chris