C-DUB

Is the 4T45E on the SS exactly same as the reg HHR?

Reading some places that reg hhr tranny only rated to 230ish ft lbs, but the SS is well beyond that even in stock form?

843de

The engine tuning on the SS auto is dialed back a bit for the health of the transmission, while the 4T-45E is the same, there is a difference in the final drive ratio.

This thread goes into that in some more detail, just click the link below.....

https://www.chevyhhr.net/forums/fuel-economy-hypermiling-47/mpg-versus-final-drive-gear-ratio-28913/

2005HHRauto

Not 100% sure, but...
I've heard that some of the parts within the SS auto are better, &/or more durable.

Items such as input shaft , sun gear shell, ect , are supposedly 'hardened', to withstand more torque.

I've been putting 450 foot pounds of torque thru mine, for several years now, with an Ethanol tune, & it is still super strong.

There are some things that you must do, to handle more torque.

1. Synthetic fluid is a must. Heat is, & has always been, the 'enemy' , of every automatic.
2. Reducing 'shift' time in half, via HPTuners, as a quicker shift, reduces the heat, & friction of the shift. In the 'old' days, this was done by putting in a shift-kit.
3. Doubling the torque 'managment' , below 3,500 RPM, via HPTuners. Most guys delete all torque management, & wonder why they blow-up automatics on the street.
4. NO 'sticky' wide tires on the street. Chose good quality , good handling, good comfort, street tires that don't 'dead' hook-up on the street. Unless you like replacing trannys. A little wheel spin, & chirping tires, will make your automatic last a long time. There's a 'reason', why GM chose the OEM tires that we have, for reducing drivetrain warranty costs...

C-DUB

Only reason I ask is because a friend of mine had an 06 HHR LS, and the tranny pooched after only 115,000 km and they don't have any power at all!?

Leads me to think something else happened... or just a lemon.

2005HHRauto

If the fluid wasn't changed, it was a death sentence...

Tyler Harvey

For a tranny to go that soon, tells me something wasn't being looked after.

hyperv6

That is the truth on the OE tires as they have so little grip. I was so glad to remove them as in the wet they were just getting worse and worse.

I tend not to just hammer it from the start so it will not hammer the tranny. The car hooks up better anyways. Sometimes less is more.

Note the GM tune is 315 FT LBS on this tranny and 340 FT LBS in the 5 speed Solstice. That should tell you something since they keep the warranty on it. there is a little more room but you have to be careful.

The GTP guys with no engine management on the 04 and later cars were taking the transmission out at around 325 HP in the Series III SC engines.

RevvAutoss

470 ft lbs here and some serious abuse so far, nothing exploding yet.......(fingers crossed) Haha i also only spin so the trans is probably perfectly happy atm.....Maybe i shouldnt put these 245 nitto 555's on my new wheels . Opinions?

bugflipper

If they are the nt555r tires it'd be best to keep them far away from it.

I run them on some street rods in the 325/50/15 size. You don't even need to warm them up. They are a lot stickier than a hoosier or mickey thompson dot drag tire. They even have a lot more traction than the cheater slicks.