2-1 bang shift

[Glava2876]

I started this tread in another area, but figured it may make sense to put it here also.

My new Denali 6.2 A8 started the 2-1 bang shift that can feel like you were rear ended.

I also have a 2015 Corvette with a M7, but the Corvette uses the same basic A8 speed and I noticed some similar complaints about the A8 on the Corvette Forum -so I asked about it on one tread, letting them know it was in my GMC and got this response;

 

 

The 2-1 bang is a 0 pedal driver demand issue. The factory table has large negative torque demand at 0 pedal coming down in speed and when you get to 0 mph it demands 77 ft lbs (axle torque) from like -400.

I have been working with the driver demand table in the low speed / low (or zero) pedal areas as well as the downshift speeds/torque converter unlock speeds and have nearly eliminated the issue.

A large percentage (almost all) of the A8 issues are due to poor programming and don't need a transmission replacement. GM needs to crack some heads in their computer nerd dept and write some tunes that work better.

 

 

I am not the sharpest tool in the shed and it may not be right, but I thought I could try giving a little gas with my right foot while braking with the left to see if more than 0 demand made any difference. It did and depending on the amount that I pushed the accelerator while I braked, the bang was just barely perceptible or gone.

So is there a way to get a tune to do that?

[GMC-AT]

A lot of these trucks ( 6 and 8 speed) do this. Search about adding the leaf spring clamps .... it does help the issue.