Phantom shifts of Transfer Case or Tow Haul Mode

DasGoob · December 28, 2023

2019 Chev 5.3 8 speed trans RST: I am having issue with phantom shifts/attempt to shift of transfer case as well as the (more often) phantom tow/haul mode activated or phantom sport mode activated. Anyone ever seen this? I am wondering if there are issues with the harnesses behind the panel since they share a whole panel in the truck.

Any help is greatly appreciated. Had this occur occasionally when under warranty and they checked but of course never acted up for them and no indication when they ran diag. Now it is 60k miles and starting to get more frequent. Just worried it may go unnoticed by wife or try when just at worst speed. Any help is greatly appreciated.

GMCustomerService · January 5

On 12/28/2023 at 4:30 PM, DasGoob said:

2019 Chev 5.3 8 speed trans RST: I am having issue with phantom shifts/attempt to shift of transfer case as well as the (more often) phantom tow/haul mode activated or phantom sport mode activated. Anyone ever seen this? I am wondering if there are issues with the harnesses behind the panel since they share a whole panel in the truck.

Any help is greatly appreciated. Had this occur occasionally when under warranty and they checked but of course never acted up for them and no indication when they ran diag. Now it is 60k miles and starting to get more frequent. Just worried it may go unnoticed by wife or try when just at worst speed. Any help is greatly appreciated.

This is certainly not what we like to hear, DasGoob. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your 2019 Chevrolet Silverado. To do so, please send an email to [email protected] with ATTN: DasGoob/GM Trucks in the subject line.

Please include your contact information, VIN, a brief description of your concern, and the name of your preferred dealership. We look forward to hearing from you. To learn more about GM’s Privacy Policy, please visit https://www.gm.com/privacy-statement.html. The information you provide may be monitored and recorded and is subject to the GM Privacy Statement.

Privacy Statement | General Motors
Your privacy is important to General Motors. This Privacy Statement addresses the personal information GM collects and how GM handles that personal information.
www.gm.com

HondaHawkGT · January 13

On 12/28/2023 at 3:30 PM, DasGoob said:

2019 Chev 5.3 8 speed trans RST: I am having issue with phantom shifts/attempt to shift of transfer case as well as the (more often) phantom tow/haul mode activated or phantom sport mode activated. Anyone ever seen this? I am wondering if there are issues with the harnesses behind the panel since they share a whole panel in the truck.

Any help is greatly appreciated. Had this occur occasionally when under warranty and they checked but of course never acted up for them and no indication when they ran diag. Now it is 60k miles and starting to get more frequent. Just worried it may go unnoticed by wife or try when just at worst speed. Any help is greatly appreciated.

Watch this video at 14:05 and see if it sounds like your issue. He mentions that they eventually determined it's a loose ground.

https://youtu.be/VBvGSEEn8es?si=xEgF6t-0fRFiAhge

10 under · January 13

My tow haul wire was cut under the steering column cover, had to splice In a new section of wire

DasGoob · January 15

On 1/12/2024 at 7:20 PM, HondaHawkGT said:

Watch this video at 14:05 and see if it sounds like your issue. He mentions that they eventually determined it's a loose ground.

https://youtu.be/VBvGSEEn8es?si=xEgF6t-0fRFiAhge

This is similar. It is a possibility but the video does not show the ground specifically that is an issue so I am not sure what to go after. It happens not just for the transfer case with me, but also tow/haul mode or sport mode. Just randomly coming in without my interaction. Beings they are all in the same harness on the back of the dash pullout, it definitely sounds like a ground issue that could cause all of these issues. I should dig further on this to see if I find anything.

Thanks for this. If you have more info on the ground he speaks of, please let me know. Again..... thanks.

DasGoob · January 15

On 1/13/2024 at 4:48 AM, 10 under said:

My tow haul wire was cut under the steering column cover, had to splice In a new section of wire

It is not a simple "doesn't work" or "won't turn off" issue. It is a random engagement issue and not just tow/haul mode. It is perplexing as nothing that I see on the harness is common for it.

DasGoob · January 15

On 1/7/2024 at 5:04 AM, dghuai said:

All I have to do is lift off the throttle, and if the vehicle senses it’s not slowing it downshifts. It also works very well with the cruise control, even in hilly terrain. But I only use cruise in the dry…in the wet I want that immediate control.

192.168.100.1 192.168.1

This is a great feature of the vehicle that I do like, although when in normal shift mode, only occurs if you drag the brake for a bit, and always works in tow/haul mode. I get that and it works well, but my issue is separate from this feature.