I have an 06 tc and its rear suspension makes a hard solid thump when driving over a speed bump. It sounds like the hatch closing. It feels like I have no suspension because it feels like a blunt drop. As for normal driving, I have no complaint.

Is this normal? If not, what should I check for?

 

sounds like you might have a bad strut and are riding on just the spring.

 

how fast are you going over the speed bump? if it does that when you barley creep over the bump going as slow as possible then yes you have a bad struts in the back. The way to test if you have bad struts is called the jounce test. to do this test you go to the rear bumper and push down on it with all of you body weight 3 times until the car is bouncing. you count how many times the car bounces.it should go up and down 2 times before returning to normal. any more than that and you need a strut

 

I had this too, the bolt on top the passenger side rear strut wasn't tightened all the way. I tightened it and haven't heard the thump noise since.

 

either a loose bolt or your struts are blown