Can I just add marvel mystery oil to transmission and crank it up and let it run through for a few minutes?

 

Of course you can. It’s your HHR, but I don’t advise it, it’s not going to correct burnt out solenoids.

 

Burnt out solenoids? Is there a how to tutorial on checking transmission levels?

 

Is there a puddle under the car, that's the only place fluid can go.
https://www.chevyhhr.net/forums/how-...-change-58325/

 

Yes there is... Which is new to me....🙄

 

Is that puddle a reddish fluid?
is that puddle the size of a quarter? Or larger?
if you look up under the transmission do you see where the leak is , where the fluid is coming from?
could it be the output shaft seal leaking on the passenger side?