Hello everyone. Although I have this site saved in my bookmarks, this is my first post. I have an 05 Mercury Mariner (134,000 miles). I replaced both front sway bars last summer, and now I am hearing that familiar knocking noise again.. Ugh! This time, from the back.. This may be a dumb question, but I am slightly mechanically challenged....... Is there a difference between the front and rear sway bar? I was just going to order them online and do it myself, but don't want to get the wrong ones...

 

I am going to guess you mean sway bar links. I don't know if the Mariner is different (I have an escape) but we do not have a rear sway bar. Could be shocks have gone bad and are now knocking over bumps.

Hope this helps.

 

I would not expect the front and rear sway bar links to be the same. The fronts have a rod that connects the end of the sway bar to the lower control arm. The rear sway bars have no such link, they are mounted directly in a rubber bushing.
I would get a piece of cardboard, and slide under the rear of the vehicle to do an inspection. You might find loose shock mounts as noted, or loose sway bar attaching bolts where they attach to the rear suspension or to the control arms. You might also find the lower control arm bushings have deteriorated. Take a good light, and shine it all around looking for stuff that looks loose, or has wear or tear marks showing movement.
Your Mark I mod 0 eyeball is a good tool for this, and your knowledge gained of what is 'loose' will be a tool in your tool box if you have to go to a shop to get things replaced. YOU saw what was/was not loose, torn, or worn out, so a shop cannot pull the wool, not that they would... Just looking at it will be reassuring.
tom