Laggy Down-shift

Mike

Original poster
Member
Apr 8, 2012
42
Hoping someone can offer some advice here....

I have a 2011 Suburban LTZ with 13k miles. Im the 2nd owner. I've had it about a month now. My question/problem- laggy down-shifting.

As I slow down, around 25 MPH or so, things are ok. As I begin to accelerate the motor feels very sluggish. The best way I can describe it is to say, imagine driving a stick-shift car and start slowing down, then need to accelerate. As you press the gas you get that sluggish feel before you down-shift. It doesnt do it as bad when I have the shifter in the "M" position. When I'm in "D", its much worse. Dealer says this isn't a problem. I have trouble believing its normal operation.

Can this be corrected? This is annoying enough to make me wanna dump the car. My 2007 'Burb LTZ didn't do this, nor did the 2008 Denali I was using as a loaner last week.
 

dla442

Member
Mar 31, 2012
249
grand rapids, mi
Perhaps the torque converter is not releasing right away giving it that starting out in 4th gear performance. If you give it more gas does it get better?
 

Mark20

Member
Dec 6, 2011
1,630
I had something similar if not the same in a Pontiac TranSport. Since I was well within warranty I took it in. They ended up reprogramming the transmission (whatever module actually controls it) and all was well. Operation like that is NOT normal. If the service writer does not want to help start moving firmly but politely up the chain.
 

Mike

Original poster
Member
Apr 8, 2012
42
dla442 said:
Perhaps the torque converter is not releasing right away giving it that starting out in 4th gear performance. If you give it more gas does it get better?
Thanks for the reply. If I punch it, its fine. If i just lightly apply the gas, it takes a second or two before it down shifts. Part of me feels like it might even be hanging up in 4 cylinder mode and not getting back to 8 cylinders quick enough.

The service manager I'm dealing with has been pretty cool with everything. They just replaced my cracked dash and power running board motor under warranty. I know the cracked dash issues have been pretty widespread. The same guy also blamed the cracked dashes on people using Armor-all. I dont want to end up in the same boat with the tranny as I did with my 2003 LT EXT Trailblazer. I knew there was a problem, GM knew, but no one would address it until I had to replace it a year after warranty ran out.
 

dla442

Member
Mar 31, 2012
249
grand rapids, mi
I just did the pwm tcc fix on our TB. Now that the converter locks properly we also have to give it a little gas to get it out of lockup. I think this is normal. If I push the pedal a lot it will just shift into first or second depending on speed of course. Are you giving half push on pedal, one quarter etc? Not sure how the newer trans are or if same as ours but I think most TB your have give a bit more gas to get Tc out of lockup during lower speeds,like 40-55 mph. Do you have this problem on the expressway at higher speeds when you accelerate?
 

Mike

Original poster
Member
Apr 8, 2012
42
dla442 said:
I just did the pwm tcc fix on our TB. Now that the converter locks properly we also have to give it a little gas to get it out of lockup. I think this is normal. If I push the pedal a lot it will just shift into first or second depending on speed of course. Are you giving half push on pedal, one quarter etc? Not sure how the newer trans are or if same as ours but I think most TB your have give a bit more gas to get Tc out of lockup during lower speeds,like 40-55 mph. Do you have this problem on the expressway at higher speeds when you accelerate?
Usually anything less than a 1/3 pedal won't make it down shift. I know something more is f-ed up. My rear wiper motor wasn't working and had it fixed. I had my dash replaced immediately afterwards. Never tested the motor. Went to use it and it didn't work but the "service 4wd" light came up. stayed on all night between running errands. Now 4wd light is off but wiper doesn't work. This ordeal has been an absolute nightmare. Wish I had my 07 LTZ back, lol.
 

DrData

Member
Nov 8, 2014
17
Whatever became of your issue? Any solution found?
 

Forum Statistics

Threads
23,272
Posts
637,481
Members
18,472
Latest member
MissCrutcher

Members Online