Going Up to the Mountain with 8V AWD

nasser · #1 (**permalink**) 12-20-05, 02:30 PM

Today was my first trip to the mountain with my new 500 miles 8V AWD and I felt like driving a 4 Cyl car !!!! if I am driving at moderate speed , 50 miles and above it feels normal , but if I am driving on low speeds , i.e. below 30 miles/hr , the transmission keeps on shifting as if it is a 4 Cyl car that lacks power , I tried the manual shifting but it didn’t feel any better – I am sure there is something wrong cause I have driven the northstar engine on both my STS 95 and STS 98 for 10 years now and never experienced this feeling before .
My first 500 miles were covered on the highway and was almost normal . Any comments ??

nasser · #2 (**permalink**) 12-21-05, 12:39 PM

after more driving up the hills , i noticed that the funky shifting is only at low revs ( 1500 to 2000 rpm ) and between 2nd and 3rd shift , any one with the same feeling ?

tedasaurus · #3 (**permalink**) 12-21-05, 01:39 PM

I too have a '05 V8 AWD and I am spending time with it in the mountains in New Mexico right now. I have noticed shifting indecision around 30 mph. Sounds similar to the problem you are complaining about. I presume it is simply a software problem and will ask Sewell Cadillac back in Dallas to look at it when the next service is due (10k now). Seems even reviews of the STSV note a hard shift between 2nd an 3rd upshift in level driving. My car has this issue as well.
On another note, many cars perform strangely when the altitude rises. I have had idle and shifting problems on other late model makes as well when driven above 7,000 ft. Guess the computers can't forsee everything.

nasser · #4 (**permalink**) 12-22-05, 11:37 AM

Dear Tedasaurus

please let me know if you suceed with your dealer , cause my dealer is saying that this is normal

i can't belive it , i feel like driving a 4 cyl car

Dooman · #5 (**permalink**) 12-22-05, 12:41 PM

The Northstar really needs to rev to stay in the power.. I feel it in the hills on my older model here in New England..

nasser · #6 (**permalink**) 12-23-05, 06:12 AM

i had the 1998 northstar on the sts but it was very smooth , very good torque even at low rpm and never noticed any funky shifting while going up hills , but the 06 is really annoying

Fred_Mac · #7 (**permalink**) 12-23-05, 08:15 PM

I really think it has a lot to do with GM trying to squeeze out the best MPG possible. It's not like the power isn't there when you need it ... it's just that the shifts seem to want to keep the engine in the 1500 to 2000 rpm range during normal low speed driving.

ascariSTS · #8 (**permalink**) 12-24-05, 06:04 AM

lol I wonder how you can drive this slow uphill.. i'm always pushing it hard and still STS wants more... I can feel every single blood cell in my body when I push it hard uphills... it feels like you are a part of the car, connected in one piece... especially when it comes to cornering and magna ride does its job...

lol.. I can't imagine driving like 40 mph... boring for me

**Playdrv4me** · #9 (**permalink**) 12-24-05, 01:12 PM

My 2001 STS always had issues with shifting indecision at lower RPMs right around 35-40mph. It would keep kicking down for no reason.

nasser · #10 (**permalink**) 01-14-06, 11:08 AM

took my car to the dealer and left it for 3 days so they can drive it and test , but they said nothing is wrong ???? i can't believe it
any one facnig the same feeling ? is it only on the AWD ?

ascariSTS · #11 (**permalink**) 01-14-06, 03:55 PM

suggestion... This might work

Don't put the transmission on "D"... put it on "4" instead

try it out and let me know

GrannysRedSTS · #12 (**permalink**) 01-18-06, 02:09 PM

I live at 3200 ft. I have 05 STS Northstar V8 AWD. Fairly steep climb on my daily commute. Never felt anything like what Nasser is experiencing. Very smooth ride, great power. Took it to Lake Tahoe in the snow and had no problem there, either.

tedasaurus · #13 (**permalink**) 01-20-06, 02:20 AM

Quote:

Originally Posted by nasser

took my car to the dealer and left it for 3 days so they can drive it and test , but they said nothing is wrong ???? i can't believe it
any one facnig the same feeling ? is it only on the AWD ?

I have the same problem with my '05 STS4. It is subtle, but after living with it for awhile I am torn whether it is the tranny or something along the lines of a bad throttle position sensor. The reason I say this is that after it shifts it does not want to downshift appropriately/progessively (like almost a dead spot followed by indecision) unitl you mash the gas pedal so far down that it skips two gears and blasts you ahead. I have had Cadillac TPS's go bad and this is not far from that. Granted the new car is drive by wire but it has to get its readings from something.
I will have the car looked at next time it is ready for an oil change. I will post a cure if there is one.

nasser · #14 (**permalink**) 01-22-06, 04:27 PM

Quote:

Originally Posted by tedasaurus

I have the same problem with my '05 STS4. It is subtle, but after living with it for awhile I am torn whether it is the tranny or something along the lines of a bad throttle position sensor. The reason I say this is that after it shifts it does not want to downshift appropriately/progessively (like almost a dead spot followed by indecision) unitl you mash the gas pedal so far down that it skips two gears and blasts you ahead. I have had Cadillac TPS's go bad and this is not far from that. Granted the new car is drive by wire but it has to get its readings from something.
I will have the car looked at next time it is ready for an oil change. I will post a cure if there is one.

hi Shane
took my STS for a long ride last Friday to the mountains and couldn't explain the situation better than you did , this is exactly what I have noticed , and to add on it when I need power after finishing a curve I have to press the pedal almost half the way then suddenly the gear shifts one or two gears down and the car jumps - I tried to drive on 4 instead of D , tried the manual shifting , but still no good . however if you drive aggressively and at height speed/rpm you will not feel this problem , but if you are driving calmly it is very annoying
any way , I met today the general manager of the dealer company on a Sunday lunch at a restaurant and he told me that this has something to do with the PAS ( personal algorithm shifting ) system , and the computer will check how you’ve been driving in the past and adjust the shifting accordingly !!!! I couldn’t discuss the matter with him in more details because we both had our wife’s with us ( you know ) so I told him that I will pass later to discuss it more
please let me know what your dealer will tell you after inspection
note : I have only 1000 miles on my odometer

tedasaurus · #15 (**permalink**) 01-23-06, 01:27 AM

I do not believe it is the PAS, although I do think the tranny needs a better software update if one is available, which is along the same remedy. Probably a combination dilema between throttle mapping versus transmission programming for good mileage. Seems like many new cars have electronic tranny hicups.