Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 10 of 10 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I have an 04 Trailblazer LS 4x4 that is all stock and around 170,000 miles. I have a sudden jerk/shudder anywhere from 45 to at least 75 MPH. I have checked the codes and the only ones are a coolant temp too low and secondary air injection system code. I thought it may have been due to old transmission fluid so I changed the filter and flushed by starting up the vehicle and leaving one of the cooler lines off until new fluid came out. This had very little impact on the shuddering. I tried the brake switch test and so far the shuddering stops when activating the brake switch. I have tried keeping the brake pressed and shifting into drive and lightly accelerating and no shuddering or surges are noticed. I am just looking for some guidance for next steps.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
Thank you for the information. I had the parts to fix the PO128 code on the way and will try to get to that next week probably but I was just curious what would be the next steps to troubleshoot torque converter related issues?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #8 ·
I just replaced the thermostat and it did fail open but still need to test drive it. The jerking is worse some days and then other days almost none. It mostly occurs on the highway in cruise from 45 to 75 mph. The rpms may vary some but it is extremely slight
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #11 ·
Where is the best place to get this TCC valve kit?

I will have to take a drive and keep a closer eye on rpms but I do not think mine moved that much, seemed more consistent.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #17 ·
Thank you for all the good information so far. I will give the TCC valve a try. Is it just the mechanical valve swap or is there any software work required?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #19 ·
I installed the valve kit but it did not go away, actually seems a little worse now. Engine seems to be running smooth with no issues. I am guessing the torque converter is on the way out….
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #23 ·
Update: I changed the plugs on a whim with 41-103’s and also re-cleaned the throttle body and really payed attention to getting it extra clean. I took a short test drive and seems to be acting much better. I will have to put some miles under it to know for sure. I appreciate everyone’s advice and input.
 
1 - 10 of 10 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top