Hi I have a 2007 Chevy hhr 2.2 litter Lt and it is shifting harder then normal. I have no check engine light and got tramsmission fluid flushed 8 months ago and just got it check and the dealership said the fluid is clean and good. What could be causeing it to shift hard? When I'm in traffic stoping and going it feels like it's slamming hears when it shifts. The car had a automatic engine with 160k miles on it.

 

Give the search a try.

Among the things you will find (and most likely your problem): overheating or underheating. Check your coolant level both in the bottle and under the "radiator" cap. Could also be t-stat is bad.

Look at the coolant temp, it should get up to 180F in less than 10 minutes or so and stay between 180F and 220F all the time.

 

When you had it at the dealership to be checked, did they not look into the cause of the abrupt shifting?

 

No they didn't because I asked to have the tranny fluid checked and that's all they did.

 

I agree with Donbrew can't hurt to check

 

when you get a check engine light comes on most of the time it is the pressure control valve going bad and are common with the automatic trans that we have.. i do have this problem but it comes and goes only when there is moisture in the air ...my be having something to do with the connecter causing it ..i have the same year and motor

 

I thought it might be a sensor in the transmission but I'm not geting a check engine light so could it be something else?

 

Even if you don't get a CEL, it could still have a trouble code stored in the computer.
Try pulling the codes and checking for stored ones.

 

So, I was just wasting my time when I typed post #2?

 

Apparently we are, Don! I'm out!