I've been around the forums and want to see if I can get some solid info from the tribe here. My daughter has a 2011 HHR LS. It's an automatic and since she's had the car (20 months) it has revved up while shifting into 4th gear. Once it "locked in" to that higher gear it was fine for however many miles until she came to a stop and it would repeat the cycle.

Yesterday, it started slipping badly while driving (ie, rpm not correlating to speed). Today I test drove it and even in I drive it seems to be slipping (3rd gear?). Based on how it's acting, I'm prone to think the tranny is shot. There are no stored codes which leads me to believe it's not a solenoid issue.

I'm currently adding some Lucas "stop slip" magic potion and don't expect much from that but it's a hail Mary at this point while we're sorting things out...
The vehicle has about 159,000 miles (had 140k when she bought it so she doesn't drive all that much and mostly local)

Assuming the trans is bad, my main question is whether or not the transmission from a 2008LS HHR will fit into it? Other than year, the vehicles are pretty similar. I realize that these transmissions are computer controlled so not sure of the interchange. I have the tools and equipment to where I could accomplish a switch (low on incentive though). My shop also has a hoist.
Note: we have the entire 90k miles 2008, it had some front end damage and was totaled by the insurance company even though it was still driveable. It now has a salvage title so it's not an option to repair here in Georgia (would have to be done by a state licensed rebuilder)
Thanks for any input.

 

A , you could replace the transmission solenoids
B, you could swap transmissions , in which case I suggest you install new solenoids into that one.

seeing as you have a low mileage used transmission, plan B would be my choice.

 

Do you know if the 2008 transmission would be compatible with the newer 2011 car? Would I have to move electrical components around? I would really hate to go through the work of removing two transmissions and installing one and then discover it won't solve my problem. I'm pretty sure this isn't a solenoid issue from the way it's acting. I could disassemble the transmission and rebuild it but I would be pretty far into new territory for me. I've had automatics and manuals apart before but I'm a long way from being a transmission technician. I've done lots of engine work but transmission stuff is mostly clutches and changeouts. I have a well equipped shop, all the tools but I'm fat and old and it seems like a lot of work, lol.
Everything I'm seeing online indicates transmissions are interchangeable between 2009 and 2011. Since I have a 2008 I'm concerned it won't work for whatever reason.

 

Added info, both of these vehicles have the 2.2 engine.

 

We're assuming that you have checked the fluid level?

 

Car-part.com does show only 2009-2011 2.2L HHRs as suitable donors for a 2011 transmission. Interestingly, they also show the 2008 automatic transmissions are different if produced through 1/6/2008, versus the ones produced 1/7/2008 and after.

I bet the difference between 2008 and 2009-2011 is a gear ratio change (to accommodate the VVT that was added to the 2.2L perhaps?).

I have personally swapped a 2007 2.2L HHR automatic transmission into a 2011 2.2L HHR. It's still running fine for my daughter. Everything went together normally, including the electrical connector.

Steve

 

That's good to hear. I may just give it a go if it will bolt in and drive. The donor car was built in 04/2008

 

The fluid level isn't an issue. Also, the fluid and filter was changed about ten thousand miles ago and looked normal.

 

As fastsuv stated the 2007 transmission bolted up and drives great in a 2011. Some charts don’t even mention the 2011, some show from 2005 to 2012 production of the HHR , so take there listings with a grain of salt.

 

The donor car has been moved into the shop. Let the fun begin!

Would it make sense to drop the whole cradle? ie, engine and trans combined? The donor car is unlikely to ever be on the road again. I may eventually use the engine in my 2008 LS that now has 253,000 miles on it and uses a quart of oil about every 1000 miles or so.(now mostly local driving and pulling a trailer 75% of the time) It's got the original clutch in it still and if I have to split it to install a new clutch I may just switch to the lower mileage engine (same year engine)