So my friend has a 2007 HHR, and whenever you drive it you can see the RPM's changing in the dash but there is no shift shock and the engine doesn't sound like it is shifting gears. The engine noise changes pitch and loudness depending on how fast you are driving, almost like it is stuck in first gear. I can drive in on the freeway and take it above speeds of 60 mph so I am very confused on what it may be. Any suggestions?

 

Welcome to the site

Sounds like the trans is not shifting correctly. I would stop by your local parts store and get the codes read. It may give you a place to start.

 

aboard!

Not too likely that it's hung in first, it would be bouncing off of the limiter at highway speeds.

Good advice from Lucky on having the codes pulled, but be forewarned, the majority of "parts store" code scanners will not display transmission trouble codes.

You may want to take it to a Chevrolet/GM dealership where they will have a Tech II scan tool that can view every code, either "stored" or "pending".

 

My wife just reported this issue to me last weekend, I plugged in my code reader and there were no codes, I ensured all of the fuses and relays under the hood in that fuse box were tight and secure some pushed down a bit fuse 43 a bit more.
After a week of 90 mile trips to work a and back she states problem solved!
Worth a shot, it's the black plastic box in front of the brake master cylinder under the Darth Vader helmet!

 

It's weird that it would be a fuse problem but at this point I'll try anything. Thanks guys.

 

Impossible for the fuses to back far enough out to cause a problem. Look at the inside of the lid to the fuse box.

If pushing down on the fuses helps with the problem, I would suggest you have the traditional problem with the 2 piece fuse box itself. Pushing down reconnects the faulty pin(s), thus resolving the issue. Eventually you'll need to correct the fuse box problem.

There is a TSB on this issue.

 

I addressed the fuse panel halves issue also so maybe that issue has resurfaced, I'll check it when I get home.