The MN5, 4T45E automatic transmission in the HHR SS is the same unit used in all other applications. The HHR SS has a different final drive ratio though.

2009 Hydra-Matic 4T45 Transaxle ( MN5 ) 3/18/2008
Type: four speed front-wheel-drive, electronically controlled, automatic overdrive transaxle with electronically controlled torque converter clutch
Engine range: 2.2L - 3.5L
Maximum engine torque: 221 lb-ft (300 Nm)
Maximum gearbox torque: 325 lb-ft (440 Nm)
Gear ratios:
First: 2.95
Second: 1.62
Third: 1.00
Fourth: 0.68
Reverse: 2.14
Final Drive Ratio: 3.05, 3.29
Maximum shift speed: 6900 rpm Sprocket Ratio Dependent
Maximum validated gross vehicle weight: 2220 kg (4884 lb)
6-position quadrant: P, R, N, D, I, L

 

I didn't say that - mrarff said that a few months back and I picked it up as an ironic quote in my sig. Notice the WTF and the LOL I put after it? I am CONVINCED this is a hot rod!

 

Not sure if anyone would really see a marked difference in reliability these days in the long run.

I would select the transmission for the driving that you'd be doing. I personally like the manual trans, because I live in a rural area and have fun shifting on back road runs. If I lived in the suburbs or the city, I probably would have opted for the automatic.

But some like manual all the time and others like auto all the time. Go with your driving style preference and call it a day...

 

If I had to do it again I would have bought the manual. Just for driving thrill. the automatic did have one issue. I love to beat the piss out of her and she did have what they said 'catastrophic falure'. I blew the planetary gears up inside the case. Case was ruined, and they put new tranny in. It could have just be a bad tranny from the line since it only had 21000 miles on it, but it did happen when I was racing :) Hooked up hard and BAM.... done!

Buy the manual.... just better and you wont feel like you cant modify it like I do. i am worried I will just shell out another.

 

I got the 5spd at the time because I wanted the extra 25-30 hp, the Brembo brakes and the limited slip diff. It's definitly a blast, but is also a pain around town here in NY. You'll get the power back in an auto with the Stage 1 upgrade if that's all you require. I wish I had the auto with the performance package, but that combo was not avail in 2009. Also, my wife always nags me about her not being able to drive that stupid car with a stick. "That was a dumb choice" she says. Oh well.

 

Well, I would hate to have to change a slave cylinder on a stick (out of warranty).. nuff said..

 

Yeah, where do they hide the slave cylinder? Girlfriend had a Chevy Cavalier manual which had a slow leak there. We managed to limp along topping off the fluid until the controller for the airbags got wet under the seats and we sold the vehicle because it would have cost more to fix THAT then the vehicle was worth. She loves how much her HHR improved over the Cavalier!

 

I'd love to have a stick, but my auto was a life saver when I got stuck in traffic on the Mass Turnpike Monday morning going to Boston.

 

I defenitely hear ya. How many out there got the auto, w/ the Brembos and the L.S.D. That's got to be the killer combo with upgrades. Consistency and boost stays up.

 

I thought I heard somewhere that the automatic can't be had with LSD...?