I have a 2006 envoy denali with 106k miles. Today(03/31/14) the transmission started shifting very very hard from 1st to 2nd. It shift so hard it will "bark" the tires. shift little hard from 2nd to 3rd and little less hard from 3rd to drive. I havent noticed any slipping. What could cause this problem? fluid is full and clean. thanks in advance
2006 envoy denali shifting hards with no slipping
- Thread starter N.SHIFT
- Start date
C-ya
Member
- Aug 24, 2012
- 1,098
is this under any throttle condition? If under light throttle, I would suspect a partial clog somewhere perhaps or a worn plate/hole/ball. Under heavy throttle, maybe a plate/ball is wearing. I know when I did the shift kit in my Firebird (TH350), you replaced the separator plate with theirs and leave out certain balls (or add them... been a while!). If I drove it normal, it shifted normal. If I was on it hard, it would bark from 1st to 2nd at 65ish and a little squeal from 2nd to 3rd at 85ish.
Somebody else will be along with the right answer soon, I'm sure. I haven't delved into auto trannies any more than that. I just noticed my TB doing the "shuffle" once or twice, but no CEL yet. I think I'll be doing a PWM eliminator kit this spring when I change the tranny fluid.
Somebody else will be along with the right answer soon, I'm sure. I haven't delved into auto trannies any more than that. I just noticed my TB doing the "shuffle" once or twice, but no CEL yet. I think I'll be doing a PWM eliminator kit this spring when I change the tranny fluid.
its under less then normal driving. Started few hrs ago and I been trying to baby the crap out of it. I was on my way to work. couldnt turn around and go home so drove it on in. it doesnt bang or slip. Just shift very hard. 1st time it did it i thought someone hit me in the rear end. stop at another red light, upon very slow take off it did it again. Next red light, took off little harder to see if that would help it. Shifted so hard the tires barked. The wierd part is i would be expecting slipping if the transmission was going out. could it be drive shaft? universal joints? rear end itsself? I am assuming its the transmission cause it eases up at you approach drive gear
IllogicTC
Member
- Dec 30, 2013
- 3,452
N.SHIFT said:
Are you checking the transmission fluid per the instructions in the owner's manual, not just sitting there cold with the engine off? Hard shifting is a common symptom of low fluid. Did you smell the fluid to make sure it doesn't smell burnt? It may look good still but could still exhibit this characteristic.
And is there anything while sitting at a stoplight? If there is a sudden "jumpiness," it could be your rear axle.
no jumpiness. fluid is red, clean and smells just like transmission fluid, check while running cold, checked while running hot. I honestly havent checked the fluid since problem stated a hrs or so ago. but just checked all fluids a week ago and transmission fluid was great shape. I was honestly amazed how clean the transmission fluid was at that point. guess it could have developed a leak over last few days but i havent noticed anything under the suv in my driveway
ill go out and recheck the fluid as soon as i get a break from work and report my findings. thanks
IllogicTC
Member
- Dec 30, 2013
- 3,452
I'm not sure if removing power to the PCM removes the adaptive shift points, but they may be your problem. It's worth a shot, pull fuses 10 and 28 in the underhood block for 30 minutes and see if this alleviates the issue.
If the PCM holds this data in non-volatile memory then you may have to find someone with a hookup for HPTuners or something to adjust it. As I understand it torque management has this problem in mind when it's operating, and it may have adapted to making the wrong assumptions on what pressure to use and what to adjust the throttle to for the duration of the shift. Some people have toyed around with the lookup tables for torque management, some have alleviated their issues with hard shifts while others just can't seem to find the sweet spot.
I'm kind of feeling it may be in NVRAM, as a guy mentioned he's had his ECU reset by the dealer 3 times just to have this exact thing keep coming up. Someone correct me on this?
If the PCM holds this data in non-volatile memory then you may have to find someone with a hookup for HPTuners or something to adjust it. As I understand it torque management has this problem in mind when it's operating, and it may have adapted to making the wrong assumptions on what pressure to use and what to adjust the throttle to for the duration of the shift. Some people have toyed around with the lookup tables for torque management, some have alleviated their issues with hard shifts while others just can't seem to find the sweet spot.
I'm kind of feeling it may be in NVRAM, as a guy mentioned he's had his ECU reset by the dealer 3 times just to have this exact thing keep coming up. Someone correct me on this?
i have checked fluid. not new by any means but def full and pretty clean. maybe just a little brownish but more red then anything. def doesnt smell burnt. i guess ill change fluid and see what happens. will also try the fuse pull 1st to see if that helps before changing fluid...thanks. anyone else?
the transmission fluid is right at the bottom of the "hot" xxxx mark on the dip stick. is this considered low? Also, it looks a little foamy(air bubbles im guessing)...not normal? normal? should i change fluid or try other things?
N.SHIFT said:
forgot to mention that about a week ago, then engine starting idling a little rough. I could see the rpm guage move slightly up and down only at idle. I assumed at 106k miles it was time for spark plug change. since then, i developed hard shift from 1st to 2nd. could all this be related to throttle position sensor instead of transmission fluid and spark plug issues? throwing the obd2 scanner on it today. will report back. thanks
I was getting the bouncing rpms at Idle on occasion, even a sporadic stall while driving. I just put in a new Camshaft Position sensor (here) and it hasn't come back.N.SHIFT said:
But I too am having the jumps between gears. The hesitation from a stop is not all the time but common. I am thinking of putting a new Variable Timing Solenoid in.
