The other day I was rolling through a covered parking lot with the windows down and when I would step on the gas lightly I would here a "Click" as the car rocked back, and when I released the gas, it would make a "Clack" as the car rocked forward.

This was all in 1st gear.
Is this normal, a transmission sound, or a worn tranny/motor mount?

I have 166,000 KM (100k miles) on my 2005 R50 Mini cooper.

 

That's really hard to say, but yes you should check all your mounts & make sure you don't have a bad CV Boot. If it helps, put the car in different gears, with the brake off & try physically rocking it back-n-forth to see if you can duplicate the sound & possibly pin point it that way.

 

CV boots looked fine when I checked. Other than the top hydraulic mount leaking everywhere (which it hasn't yet), how do you tell when a mount has died?

 

I see a motor mount in your future.

 

lol which one(s)?

 

Check the one on the passenger's side frame rail for evidence of leaking...

 

Most likely the upper motor mount...

As stated above

 

It's not leaking.
No one thinks it the transmission mount?

 

You'll either have to try the "rock'n" test or put it up on stands, get under it & have someone gently lift on the bottom of the motor with a jack to see where the movement is, one other question, I'm guessing you havn't noticed steering or handeling issues?, could also be a bad control arm bushing, you should be able to see that movement with "rocking" or "jacking" in the right places.

 

I had the LCA bushings replaced last summer after noticing steering issues.

One thing that did not change after the bushings were replaced was a creak in my steering wheel, when I turn the wheel to the left at the 10-11 o'clock position there's a creak. And if the car is stationary you can feel the wheel where it creaks, when you're moving, no real issues. Doesn't affect steering, or handling, just annoying and can't find it.

During the freezing temps of winter the creak was silenced, now that it's warming up, it is back...

Just like the rattles in my dash, and the squeaks in my seat, I've learned to live with it.... but if anyone knows how to fix it, please help.