Hi all. New to the forums, but hoping you guys can give some advice on this issue.

Got a 2007 HHR LT 2.4 w/113500 miles. I bought the car about a year ago when it was @ about 100K. Had a used car drivetrain warranty for 12K miles, but I'm obviously beyond both the factory warranty and the used car warranty.

Was driving around town locally on Friday and noticed an odd "whirring" sound that seemed to occur when driving in what I guess would be about third gear - about 2500-3500 rpms. Definitely audible over road noise at 35-40 mph. The sound goes up till about 500 rpms before the shift point and then goes away when it up shifts. Similarly, if I slow down the noise fades away completely when it down shifts.

I continued to drive the car home and then noticed it again when I drove it on the highway later that night - basically in the same rpm range/gear combination. Then, on the way home, the CEL came on. Put the code reader on it when I got home and got the P0700/P0741 combo of codes for the torque converter. I've done some reading about the code and seems that it can be anything from just simple service needed to clear a blocked/malfunctioning solenoid to needing a whole new transmission to possible MAF sensor issues.

I saved the code log and then cleared the codes - figuring it would trigger again if the issue was ongoing. I didn't drive the car on Saturday, but did a little bit on Sunday and also this morning I brought it to a couple of shops to see if they could diagnose it. Brought it first to my local mechanic and then to a local transmission shop. The transmission guy was a little baffled in general about what the cause of the noise might be. I figured that I don't know when the last time it had transmission service, so that might be the best place to start (he penciled me in for next week).

He seemed to think that if it were the torque converter it could be upwards of $800 since it's about 8 hours of labor (ouch!). Anyone come across any similar symptoms? Advice?

Also, in addition to this, after I cleared the two aforementioned codes, the car started reporting issues with the traction control system. The condition seems to clear after the car is turned off, but it comes back after a bit of driving. I had noticed that in general when I was driving on the highway lately that the car was shimmying slightly at high speeds. Nothing too overly concerning overall, IMHO. Not sure if this is a bearing issue or something with the axles (or possibly related to the above issue). I tried reading any codes even though the CEL wasn't on at all and the only thing that's coming up is the P0741 as a "pending" code.

Again, any similar scenarios or advice?

Thanks in advance!

 

The SEARCH facility for the P0741 code you received found this related link:
https://www.chevyhhr.net/forums/show...ighlight=P0741

Searching for P0700 had quite a few references - ie:
https://www.chevyhhr.net/forums/show...ighlight=p0700

Use the Search facility for further links. Good luck :-)

 

I ended up going back to the dealership where I bought the car originally. They "graciously" offered to cover 40% of the cost of whatever repairs were needed. I got a tech to come with me and his opinion was that it was either the torque converter OR the torque converter AND 4th gear! They estimated that my portion of the costs would be $1600 or $2100 - and that was assuming that I would get a core deposit on a rebuilt transmission. I'm thinking that I'm probably going to go with the independent shop. Even with the 40% reduction in prices - it still seems to be much more at the dealer.