Hi Everyone, My 2006 hhr ls has the automatic 4 speed. Does anyone else notice on light acceleration a tendancy to linger or "soft shift" the change from 2nd to 3rd? If I am getting on the Interstate where I accelerate right through to 70mph it does not do this. If my terminal velocity is around 50 or 55 its like it changes to 3rd and then engages the Torque Coverter lockup before going to 4th. I am pretty sure this may be the case because I can manipulate the throttle and jet 2 distinct ratios out of 3rd. My first automatic in 15 years so I didn't notice it until my wife drove it and said it seemed a little unusual. It does not stop pulling during this time like an actual slip.... Any thoughts?

 

Have you tried shifting it manually???

What's the reaction??

 

Mew,

I've experience the same thing as you, but right or wrong I haven't been too concerned with it. Most of the time I let the tranny do it's thing. But when I need a little more oomph I use the I gear until I get up to speed then shift into D to let go into OD. No hesitation of soft shifts in that mode....but I may ask about it when I take it in for my next service after come back from the family pilgrimage to Vegas next week.

This'll be the Toy's 2nd road trip...need to build up the mileage I've had her since June and only have 2400 miles

 

I've noticed the same thing at times. I think it's design intent.

The owners manual indicates that the gas pedal has two stages to it (can't remember the exact terminology). Press it part way down, and it gets you a bit more power, press it farther and it drops into passing gear.

That might be what you are experiencing.

 

That is the auto kickdown which drops you down a gear (or two) for passing and uphills. Used to be a mechanical lickage you could adjust. Those days are gone.



I can tell each gear when mine shifts........... IT's as hard as I let the clutch out.
(This is for the auto owners comments on the shift points thread )

 

Also the PCM has a learn mode , As to how you drive light throttle, hard throttle ect. and yes under light throttle it will shift at lower speeds & rpm into 4th gear and lockup sooner
P.S. if this is the 1st auto trans you have had in awhile they have come a long way from a turbo 350 or 400

 

That thing is just too damn smart!

 

Looking through the TSB and found "the 4T45e has new/second design control systems hardware" The cut over date on the trans mod is 12-13-05. I need to look up the build date but some of the 06 models will have the older version.

That said, I have experimented further and am convinced this is a product of my driving style. I often pull onto 2 lane hwys during my commute and no interstate.
This means I have a good half throttle down to gain speed and so the car is running 50 before it wants The 2-3 change, with momentum on it's side it shifts right through 3rd-4th-lockup during the 2 seconds or so to 55 or 60. I think the car has learned this pattern.

Yes "I" shift selection totally prevents the symptom and 2nd to 3rd is crisp and clean so I no longer fear the reaper. Thanks for the suggestions. Still getting used to the tranny having a mind of it's own. I am still surprised when (in I) it gears down for a downhill curve on it's own.

BTY, My research discovered that they use this thing (4T45e) in the Saturn Vue SUV and it's rated for up to 3.6L engines. That tells me it should last fine with the torque my 2.2 is feeding it.

 

Seems like an acceptable explanation !!!

 

GM rates our tranny for up to 205ft/lbs of engine torque, and up to 325ft/lbs of gearbox torque, with a maximum gross vehicle weight of 4,347lbs (the HHR weighs approx 3200lbs). Should give you years of uninterrupted service!