agentsmith23

So I am actually no longer a Cobalt owner, I traded my 06 SS/NA 5sp last week for an 08 HHR SS 4sp auto. I would have really preferred to have had a manual but the wife can't drive manual so we got a car we can both use. The HHR SS A/T is detuned because of the transmission specs not being able to hold 260 ft/lbs of torque. So what chevy has done is make 1st and 2nd have 235HP and 3rd and 4th have 250HP and limit torque to 221ft/lbs.

Basically what I wanted to know is if anyone on here knows if there is a somewhat easy way to upgrade the transmission to hold the extra torque. It is actually only the input side that has a low torque rating, it is rated at like 222ft/lbs but the gearbox is rated at 325ft/lbs.

For those of you with the 4T45 tranny who have significantly increased your power output what is your current torque? And have you needed to rebuild or beef up your tranny to support the mods?

The reason I asked here and not the HHR forum is because I know alot of Cobalt owners have been tweaking their cars a long time and for the most part the HHR guys seem to not know so much.

Thanks for any possible help!

riko540

ah yes theres a company that makes auto racing transmissions for the cobalts but I'm not sure if it will work for the HHR. Other than that there isn't much you can do to the transmission. Hold on I'll see if I can find the link.


Here's the link: http://www.importperformancetrans.com/gmautofwd.shtml give them a call and ask them if it will fit the HHR

HunterKiller89

iTrader: (1)

have the shafts and anything you can cryoed and then replace the clutch packs with blue plate special clutch packs. top it off with a tranny cooler.

ralliartist

that sounds like a lot of money to spend on a dd. damn.

celicacobalt

Well if you see my sig, then you'll see a tranny cooler and tuning is all my trans has on it and is holding fine for over a year.

HunterKiller89

iTrader: (1)

halfcent had his tranny reworked with i believe everything i said to do, he said it was about $2k. Do you need all of that? not really...im sure a tranny cooler will do, but what i listed bullet proofs the tranny and would probably raise it to hold over 400hp

EXsoccer1921

iTrader: (14)

is that a fully assembled 4T65 race tranny??? thats what i've been looking for

RollermanDan

No, those are about 5k... It's the 4T65HD

blackbird

The 4T40 and 4T45E are a nice design and one of GM's first fully electronic, clutch-to-clutch operation transaxles similar to Chrysler's Ultradrive/A604/41TE family (the 4T60/65E family uses overrunning clutches and are not fully electronic). With the HHR SS's automatic being heavily torque managed like so many other GM front drive automatic transaxles it's hard to say how much further you'll be able to push it. Previously it has only been "stressed" and seen severest duty behind the OHV 660 V6's in cars that weigh about the same as the HHR. If it's like the PT Cruiser turbo, I bet you'll see a few people start working with them, but someone will have to be the guinea pig in testing and pushing their car to find out what parts are going to fail and when needs and/or can be upgraded. If it's a daily driver it might take a little more power but if you really want to crank up the boost and put down a lot of torque be prepared to spend big bucks. Slushboxes aren't cheap.

Cryro treating can be great for certain wear items but you don't just want to do it to everything inside an automatic (or any transmission for that matter). The process is great for wear items like gears but also can stiffen things and in essence make them more brittle. For something like the input shaft, for example, that could be a very bad thing since the ability to slightly twist and absorb shock can be beneficial (and is why materials like 300M and certain heat treatment processes work well in many cases).

Clutch packs probably would need upgraded, the biggest trans cooler you can fit under the hood is also a great idea, but other items like the stock differential and other internal hard parts may need addressed. And since no one that I'm aware of is currently making performance products for the 4T40/45 family it's going to be new territory. As to the link on the built 4T65HD, it's a giant transaxle in comparison (although not nearly as big as the 4T80) and I'm not sure how well it would fit in the HHR. They're using them in the drag Cobalt's but I'm not sure if it would interfere with anything if it were to bolt into the HHR. Then you'd have the electronic issues with controlling it and a few other hurdles just to get it to work.

riko540

Sorry guys but the but I think the info he would want is a little farther down the page under the 4T40/4T45-E. I didn't mean the 4T60-E/4T65-E I don't think that would work.

j27

all you need is a trans cooler