Are you pulling any codes?
I've been in that boat since early 2019. Every time I switch into 4lo (sometimes going into 4hi) my vsc off light goes on and trac lights flashing. Can't remember if it happens when I lock the center, I don't think so. When I restart, it goes away, but only if in 4hi and 2wd. I usually pull a c1340 code, which is for center diff, but weirdly I haven't been able to pull that code lately when the lights come on; but that might be due to my cheap amazon ob2 reader. Long story short, some trusty mechanics and the toyota master techs couldn't figure it out after having my rig for months (replaced my transfer case, brake booster assembly, checked wiring harnesses, tested cdl). Same lights stilli come on, but everything seems to still work (4hi, 4lo, dac, atrac), so I wheel on. My next guess is it's my abs sensor or abs harness. That's the next thing I'm going to try.
Here is a link to that post:
Bizarre 4Runner Failures - What's your Story?.
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2008 V6 Sport Edition 4wd