musicman190

Seems that on even dead flat ground, from about 40 to 45 mph. My 2008 HHR LS, automatic, w/44K miles, keeps shifting from 3rd to overdrive AND BACK AND FORTH way too frequently, given that I'm holding a dead steady pedal on the throttle on a flat straight, clean, blacktop road.. By frequent shifting, dare I say, the cycle repeats every 30 to 60 seconds. Higher speeds (50 plus) don't seem to be problematic. It chooses the appropriate gear and remains constant.
A mechanic friend suggested the possibility, that even a slightly low transmission fluid level, could be to blame. Of course these vehicles don't have a dipstick to check fluid content and thus far I don't know of any easy way to gauge if its low or not.
Anyone have suggestions on possible solutions or more conclusive diagnostics?
I'm a new HHR owner and I'm just trying to seek out any & all "minor" troubles before they are serious big problems.
For Now, I suppose I'll avoid sustained 40-45 mph speeds!
Thanks for any help and I'm glad this web site exists -already...

Oldblue

Hmmm, does this shifting issue stop at say 50 mph or 55 mph. the low fluid level should also cause shift issue at those speeds.
I have an 07, auto, I have not had this specific issue, but at your 08's age I would check the level and go from there, did you notice any leaks around the output shafts or under the car?

badassbowtie

Overdrive will not take much throttle before the tranny downshifts...its really only for fuel economy...you are right at the speed that the car shifts to overdrive, so if you try to accelerate the slightest bit, its gonna downshift...it wont happen at a higher rpm or faster speed, because the engine is capable of a little more power at the higher rpm...

overdrive in reality is the tires or output moving faster than the engine itself, so comparing it to a mountain bike, Imagine moving pretty quick and your feet barely rotating. Of course if you need to accelerate at all, you need to down shift because its easier on your legs (or engine) because you are capable of more rotational force when pedaling faster..once you are going fast enough, its easier to accelerate in the highest gear, because your legs are moving a bit faster

donbrew

Where would the fluid go?
You need to get a transmission shop to take a look at it. Hopefully it is "only" a bad TCM, not a bad valve/actuator.

IgottaWoody

40 to 45 is where it starts to want to kick in...what your describing is normal..once you get up around 50 or better it will stop until a load is put on it( hill..passing) at 45 or less in OD you start lugging the motor..modern electronics wont allow that, and as soonas the load is remoed it will upshift again..viciuos cycle.

lazaino

Consider trying cruise control at the same speed you're having problems at. If the problem goes away, you're not holding the pedal as steady as you think.

Ira

musicman190

This was said to me by a friend and he thought it was normal for Chevy's. Says his chevy pick up behaves much the same. He also suggested double checking the trans fluid just to be safe. Thanks for your comments...At least, I'm not as alarmed as I originally was. musicman190

retrolled

Did you ever get this figured out? Mines doing the exact same thing, and as I said in one of my post..my sons car does not do it. You were able to explain it much better ..thanks!

Treble Hook

Is it a conspiracy, but does nobody ever come back after getting their problem fixed and let the members know what fixed the problem?

Oldblue

No , they just go and drive their HHR and enjoy the ride