Clunk in transmission from 1-2 shift.

[Shadow17]

When starting from cold and traveling down my driveway, there is a slight hesitation in shifting which then causes a loud clunk as it shifts into gear. It occurred very loudly, people turned their heads to look, when traveling down a steep grade a couple days ago. I'm sure it is the 1-2 shift.
I am assuming I have the sloppy transmission issues others have mentioned with the first gen 8-speeds.
It has the jerk into gear during high idle, and the occasional hard downshift when coming to a stop.

Anyone else know what I am talking about?

 

[Rmayrap]

yes! i hate it and pos dealer said its a known issue and no fix at the moment. also 2015 denali xl btw.

 

[Doug_L]

Anybody know if there is a fix for this? I have a 2017 Escalade (assuming it is same tranny) and sometimes have a strong kick forward when cruising at idle (ie: no accelerator applied) at low speed (say 5-15 MPH) which happens pretty often in New York Metro area stop and go traffic.
Not normally an alarmist, but vehicle really lurches forward (on this presumed downshift), enough so that I got dangerously close to the car ahead of me yesterday.
So can they re-program the transmission?

 

[Fifty]

No fix. There is a tsb with some long learning process that can only truly be done on a dyno.
Sadly the tsb says it will still do it afterwards...

I’m not sure if the black bear tuning can get rid of it. I actually liked the stock trans tuning better than the tune I got froM them. But I never logged it and sent it for a correction. So I’m not sure if they can rid the issue or if it’s a hardware problem.
It feels to me like the trans is low on fluid or the trans can’t build correct pressure to operate smoothly.

Hence the upcoming change to the 10
Speed...

 

[Shadow17]

I’m not sure if the black bear tuning can get rid of it. I actually liked the stock trans tuning better than the tune I got froM them. But I never logged it and sent it for a correction.

This concerns me as I was truly hoping the BB tune would clean up the sloppy shifting of the 8 speed.

 

[DenaliBQ]

No fix. There is a tsb with some long learning process that can only truly be done on a dyno.
Sadly the tsb says it will still do it afterwards...

I’m not sure if the black bear tuning can get rid of it. I actually liked the stock trans tuning better than the tune I got froM them. But I never logged it and sent it for a correction. So I’m not sure if they can rid the issue or if it’s a hardware problem.
It feels to me like the trans is low on fluid or the trans can’t build correct pressure to operate smoothly.

Hence the upcoming change to the 10
Speed...

there is a service bulletin they gave me that says on startup cold it takes time to build pressure hence the clunk 1-2 but thats ******** they have no fix after spending over 80k on my 16 Denali

 

[Fifty]

This concerns me as I was truly hoping the BB tune would clean up the sloppy shifting of the 8 speed.

To be fair, I never sent a log back for my tune. But it was the specific reason I ordered their tune over the other options. I had asked for the tune to correct the trans issues, and gave a quite annoyingly long log to them. Actually I sent two because I didn’t think I loaded the tube correctly. Maybe the second had the new trans tune on it, I don’t remember.

The engine tune was nice. But the trans tune was just so annoying that after resetting to stock for s service appointment I never put the tune back on.

My tuner is just sitting on my desk collecting dust waiting for a supercharger o guess.

 

[Shadow17]

To be fair, I never sent a log back for my tune. But it was the specific reason I ordered their tune over the other options. I had asked for the tune to correct the trans issues, and gave a quite annoyingly long log to them. Actually I sent two because I didn’t think I loaded the tube correctly. Maybe the second had the new trans tune on it, I don’t remember.

The engine tune was nice. But the trans tune was just so annoying that after resetting to stock for s service appointment I never put the tune back on.

My tuner is just sitting on my desk collecting dust waiting for a supercharger o guess.

Well, maybe I need to keep shopping around then. I am quite pleased with the engine performance already.
It's just the transmission shifting that is so bad. It must be a GM thing. Because my G8 was horrible too. Livernois cleared that right up. I wonder if they do tunes for our trucks?

 

[Fifty]

Well, maybe I need to keep shopping around then. I am quite pleased with the engine performance already.
It's just the transmission shifting that is so bad. It must be a GM thing. Because my G8 was horrible too. Livernois cleared that right up. I wonder if they do tunes for our trucks?

Like I said, Talk to black bear and see if they have a specific tune for this issue. I just haven’t done my due diligence