motor mount question

hi guys, quick question for the experts. i had my drivers side motor mount replaced like 3 weeks ago by the local chevy dealer and this cured all my vibration problems i was having entirely. that is... until a week ago until it started again. i believe it is my other engine mount on the pass side. isnt it true that both mounts are supposed to be replaced at the same time? cuz if this is the case i am sure i should replace my other one immediately. now how hard is this to do? the haynes doesnt help at all as usual, and i havent seen a whole lot about the pass side mount here. can i do it myself? i dont have an engine hoist but can jack the engine up just fine as long as it wont damage anything. i have no idea where the mount on the pass side is and how hard it is to get to, if anyone has a pic or anything that could just point me in the right direction that would be great!! thanks guys.

You need to check into what is causing the shaking.

Have you ever done a tuneup?

Yes its true when 1 goes it is very likely that the other goes too.

Yes its true when 1 goes it is very likely that the other goes too.

This is true, the extra workout the other motor mount will go through if the opposite does go can cause the other to fail prematurely as well.

But also we should look into what is causing the shaking in the first place which is why I called the tuneup question to the forefront.