This may be a dumb question but Can i use I Gear on the interstates w/o damaging it?

 

I had a problem (I think?) with my tranny on the way to Vegas. We were just getting close to Baker and it was about 116 degrees. I started up a little rise and the HHR downshifted and then for about the next 40 miles it would never upshift again. I was running 70mph and turning almost 5000 RPMs. Of course, that made the engine start to warm up. Nothing major but around 230. And then all of a sudden, it shifted and I haven't had a problem since.

Definitely something I will have the dealer check out once I take it in, but I know the drill. They won't be able to recreate the problem so won't know what it was.

I am sure you can use I gear on the interstate without damaging it. But why would you? You'll kill your gas mileage, and your top end speed. Not to mention that it will make your engine run hotter and harder as I mentioned above. Not something that I would want to do for very long.