If you are looking only at transaxle ratios, yes, the manual has a lower final drive but....(a very big "but," too) you forget the automatic's torque converter which is able to multiply torque when there is a substantial difference between input and output rotational speed. This ability to multiply torque is the equivalent of a reduction gear.

If you have an HHR at GVCWR (Gross vehicle combination weight rating, which is the truck at it's GVW pulling a trailer at the max. rated trailer weight) and you are starting out from a dead stop in first gear, the torque converter is multiplying torque by a ratio of somewhere between 1.5 and 2.5:1.

So...the automatic's final drive ratio, when the engine speed is high relative to the trans input shaft speed and load on the powertrain is high, is quite a bit higher than that of the manual.

For example, let's say, for the sake of discussion, the converter's torque multiplication at stall is 2:1. If you take math out the final drive in first gear with the auto, it's about 23:1. With the manual it's about 15:1.

That is one reason why trailer towing with five-speed HHR's it not recommended.

 

That is the reason they don't want you towing with any manual these days. Cause they no longer provide the "granny" first gear for towing. But it will still just as good as they auto. They just won't back it up cause too many idiots cant drive a stick for one, and the rest just don't know how to tow.