2020 Tahoe suddenly stuck in 4WD

[BEagen]

2020 Tahoe, LT, 5.3L V-8, 4WD, 11K miles. Always leave transfer case in “Auto.” Tow 2021 Jayco Jay Feather 25RB, approx. 6200 lbs, 100 mi, twice a year. Started the truck this afternoon and it was, spontaneously, in 4WD Lo! Rotating the transfer case knob to correct the setting had no effect – the light remained at “Auto” regardless of where I turned the knob and turning it had no impact. Limped it home, slowly (fortunately, less than two miles), and referenced the owner’s manual, Google, Bing, and the Tahoe Forum without any useful, relative info. After two hours searching for remedies, I went out and started the truck and it was fine! The transfer case knob was functioning in “Auto,” switched to “2^” OK, drove fine in both modes. Didn’t try either of the 4WD settings (Hi/Lo) since nothing but paved surfaces here right now (Long Island, NY). I’ll go out in a few days and try the 4WD settings but in the meantime I’m really skeeved as to why this happened out-of-the-blue. My prior, 2003 Suburban started to have problems slipping out of 4WD in it’s 17th year and I’m hoping this episode isn’t a premature harbinger of things-to-come. All comments/insights welcomed. Thanks and Happy New Year.

 

[B-train]

It sounds like you may need a bidirectional scanner to see what is happening, read codes, and perform some tests.

Also, a word of advice: only us 4wdAUTO when it's slick out and you may need 4wd. Running in AUTO on dry pavement will cause undue premature wear on the drivetrain. If you choose to do that, make sure all the tires are the same brand, size, pressure, and wear. Off sizes can cause binding as well and make it difficult to get out of 4wd unless on a slippery surface.

 

[Fless]

It sounds like you may need a bidirectional scanner to see what is happening, read codes, and perform some tests.

Also, a word of advice: only us 4wdAUTO when it's slick out and you may need 4wd. Running in AUTO on dry pavement will cause undue premature wear on the drivetrain. If you choose to do that, make sure all the tires are the same brand, size, pressure, and wear. Off sizes can cause binding as well and make it difficult to get out of 4wd unless on a slippery surface.

^^ This. A capable bidirectional scanner can show what drive mode is commanded vs the actual mode. That would give you some clues as to what's going on.

 

[Doubeleive]

meh, I drive in auto all the time
as far as it getting stuck in 4lo you might try and have it scanned with a good scanner that can read body codes and see if there is a historical code for stuck actuator or anything like that otherwise it could just be the switch going south, haven't heard of any problems with the switches since the gmt800's

 

[BlaineBug]

Try disconnecting the battery for 15 minutes firstly to see if that restores functionality.

 

[BEagen]

Thanks guys. Appreciate the responses. Bottom line: It was the battery! Replaced, reset, AOK. But, won't be running in 4wAuto mode any more. Other sources also reinforced not to use it unless the road surface is threatened. Thanks again. Drive safe.

 

[jyi786]

Thanks guys. Appreciate the responses. Bottom line: It was the battery! Replaced, reset, AOK. But, won't be running in 4wAuto mode any more. Other sources also reinforced not to use it unless the road surface is threatened. Thanks again. Drive safe.

2019 Escalade ESV here. I've been driving in 4Auto for 100k miles. I change my front diff fluid religiously, and haven't had it fail. I just prefer driving in this mode, because I find it WAY TOO EASY to spin out the rear when driving in 2WD, even on dry pavement! I can almost do burnouts when doing a u-turn when in 2WD mode.

 

[BlaineBug]

2019 Escalade ESV here. I've been driving in 4Auto for 100k miles. I change my front diff fluid religiously, and haven't had it fail. I just prefer driving in this mode, because I find it WAY TOO EASY to spin out the rear when driving in 2WD, even on dry pavement! I can almost do burnouts when doing a u-turn when in 2WD mode.

The reason they state that "4 Auto" should be used sparingly is because the 4 auto mode in our single or two-speed transfer cases is a clutch-based all wheel drive system, not the traditional viscous system found in the majority if not all of the full-time-4-wheel-drive systems. Using "4 Auto" will wear the clutches regardless of road slickness, they will receive the same amount of wear on dry pavement as they will on slick pavement, or roughly the same.