Auto tranny strong enough for stage 1?
Senior Member
Joined: 07-05-2008
Posts: 5,464
From: Akron Ohio
The tranny is fine. We seldon see a tranny Auto failure here. Now we do see a lot of clutch issues on the 5 speed.
The Auto is fine as long as you do not go a lot higher on power. The 4 speed Autos in most GM appliucations will go to 320 HP and after that you do run the risk of breaking it is you play hard.
Slicks or soft tires may be an issue at a drag strip. Wheel spin and traction control help keep the tranny alive. this is your traction relief system that will prevent a broken DIf. The dif is the weak link and mentioned above.
The reason the Solstice and Sky get a little more torque is they rew trannys will take more as will their rwd rear axles. THey have a little more strength and will take a little more power. But then they also have their limits.
The GM six speed trans axle will take even more power but will not fit in the HHR as it is too big. It will not make it into the HHR since they will replace the vehicle before any changes to the pan would be made. It is not a cheap changes as it would require new crash ratings for the new structure and GM would not put the cost into it. The same thing happened on the GTP GP. Some on their own have modified their cars for the Caddy trans axle in the past but have had to modifiy the floor pan.
The Auto is fine as long as you do not go a lot higher on power. The 4 speed Autos in most GM appliucations will go to 320 HP and after that you do run the risk of breaking it is you play hard.
Slicks or soft tires may be an issue at a drag strip. Wheel spin and traction control help keep the tranny alive. this is your traction relief system that will prevent a broken DIf. The dif is the weak link and mentioned above.
The reason the Solstice and Sky get a little more torque is they rew trannys will take more as will their rwd rear axles. THey have a little more strength and will take a little more power. But then they also have their limits.
The GM six speed trans axle will take even more power but will not fit in the HHR as it is too big. It will not make it into the HHR since they will replace the vehicle before any changes to the pan would be made. It is not a cheap changes as it would require new crash ratings for the new structure and GM would not put the cost into it. The same thing happened on the GTP GP. Some on their own have modified their cars for the Caddy trans axle in the past but have had to modifiy the floor pan.
Thread Starter
Senior Member
Joined: 06-09-2009
Posts: 2,953
From: Clinton, Mass
The tranny is fine. We seldon see a tranny Auto failure here.
Now we do see a lot of clutch issues on the 5 speed.
The Auto is fine as long as you do not go a lot higher on power.
The 4 speed Autos in most GM appliucations will go to 320 HP and after that you do run the risk of breaking it is you play hard.
Slicks or soft tires may be an issue at a drag strip.
Wheel spin and traction control help keep the tranny alive.
This is your traction relief system that will prevent a broken DIf.
The dif is the weak link and mentioned above.
Now we do see a lot of clutch issues on the 5 speed.
The Auto is fine as long as you do not go a lot higher on power.
The 4 speed Autos in most GM appliucations will go to 320 HP and after that you do run the risk of breaking it is you play hard.
Slicks or soft tires may be an issue at a drag strip.
Wheel spin and traction control help keep the tranny alive.
This is your traction relief system that will prevent a broken DIf.
The dif is the weak link and mentioned above.
Up to 320HP for a daily driver and cross-country tripper should be fine.
I'll do a couple of passes in full trim at New England Dragway on 93oc & street tires after it's been staged (Hahn or GMPP?) and slightly modded.
Then a few passes on the dyno should be all I need to see what I got for my $$$.
And bragging rights of course as the case might be
Is that 320HP at the wheels or crank?
Any chance you have the torque specs for the auto 4-speed?
Thanks
Senior Member
Joined: 07-05-2008
Posts: 5,464
From: Akron Ohio
Awesome answer
Up to 320HP for a daily driver and cross-country tripper should be fine.
I'll do a couple of passes in full trim at New England Dragway on 93oc & street tires after it's been staged (Hahn or GMPP?) and slightly modded.
Then a few passes on the dyno should be all I need to see what I got for my $$$.
And bragging rights of course as the case might be
Is that 320HP at the wheels or crank?
Any chance you have the torque specs for the auto 4-speed?
Thanks
Up to 320HP for a daily driver and cross-country tripper should be fine.
I'll do a couple of passes in full trim at New England Dragway on 93oc & street tires after it's been staged (Hahn or GMPP?) and slightly modded.
Then a few passes on the dyno should be all I need to see what I got for my $$$.
And bragging rights of course as the case might be
Is that 320HP at the wheels or crank?
Any chance you have the torque specs for the auto 4-speed?
Thanks
The 320 Hp is on a wheel dyno for most and this is where I see them start to break them.
Not the new cars also have programs in the computer that drop the engine power for only a fraction of a sec at the shift point. It makes for a smoother tranny but it also make the tranny live longer. Kind of a auto version of no lift shift.
It has been a while since I was over there but you can see who is having tranny troubles and why. It is a good place to learn what they will take on some one else's dime.
Senior Member
Joined: 07-29-2008
Posts: 727
From: Mass
http://media.gm.com/us/powertrain/en...45_MN5_ME7.doc
http://media.gm.com/us/powertrain/en...8_4T45_MN5.xls
http://media.gm.com/us/powertrain/en...8_4T45_MN5.xls
Awesome answer
Up to 320HP for a daily driver and cross-country tripper should be fine.
I'll do a couple of passes in full trim at New England Dragway on 93oc & street tires after it's been staged (Hahn or GMPP?) and slightly modded.
Then a few passes on the dyno should be all I need to see what I got for my $$$.
And bragging rights of course as the case might be
Is that 320HP at the wheels or crank?
Any chance you have the torque specs for the auto 4-speed?
Thanks
Up to 320HP for a daily driver and cross-country tripper should be fine.
I'll do a couple of passes in full trim at New England Dragway on 93oc & street tires after it's been staged (Hahn or GMPP?) and slightly modded.
Then a few passes on the dyno should be all I need to see what I got for my $$$.
And bragging rights of course as the case might be
Is that 320HP at the wheels or crank?
Any chance you have the torque specs for the auto 4-speed?
Thanks
Senior Member
Joined: 06-29-2008
Posts: 166
From: Omaha, NE
Well auto tranny lovers..... My spot free SS ownership has just been tarnished. Sounds like I busted the input shaft, but they will know more soon. I do not have the stage kit installed.
Friday night I can around a corner with some watter on ground ESC kicked in then I accelerated the car grabed and *wack*.... Car did not show signs of complete failure til Saturday after work. Park still holds car still, engine runs fine, no codes, no drive/reverse in any position, and a strange noise like something is grinding/rubbing coming straight from the engine/tranny input shaft area.
As a side note, if you have to push your HHR for a 1/4 mile or more it is surprisingly light and easy to push :)
Friday night I can around a corner with some watter on ground ESC kicked in then I accelerated the car grabed and *wack*.... Car did not show signs of complete failure til Saturday after work. Park still holds car still, engine runs fine, no codes, no drive/reverse in any position, and a strange noise like something is grinding/rubbing coming straight from the engine/tranny input shaft area.
As a side note, if you have to push your HHR for a 1/4 mile or more it is surprisingly light and easy to push :)
Senior Member
Joined: 07-15-2009
Posts: 2,070
From: Waterbury CT
Wow that's really uncanny!!! I had a similar situation happen to me on Friday. I left the local speed shop after picking up some T-bolt clamps, took a left out of there and gave her a little gas (NOO I didn't floor it!). The tranny was in "I" and I had Comp Mode on, the tires spun some on water/sand and "caught" with the ESC, then I get a CEL. After calling Onstar to see what code came up it registered P0089- fuel pressure regulator performance. I'm taking the car to the dealer tomorrow to see what gives. Mind you the car still seems to drive fine, but I'm bringing it in to make sure just for my own sanity...
