Bringing this thread back from the dead for some poor soul like me who might have been at their wit's end on this thing. Short answer is that dubveeT4R's fix took care of what has been a year long debacle for me. In case you missed it...
For anyone who is experiencing creaking coming from the dash area when it's cold and/or dry out, the source is the plastic windshield cowling. For the fix:
1) Remove the caps from the attachment points for the wipers with a small screwdriver. (Just pop them off.)
2) Remove wipers. (You will need a socket wrench.)
3) Remove rubber trim pieces at the base of both sides of the windshield.
4) Remove plastic trim pieces at either end of the cowling. (Push the center of the push pins down, you will hear a "pop", which will release the pins.)
5) Remove cowling.
6) Spray white lithium grease on all contact points for the cowling - one long strip where it attaches to the firewall, one long strip where it attaches to the base of the windshield and one strip in the middle of the cowling (underneath) where the pieces of the cowling attach to each other. Be liberal with the application.
7) Reassemble all.
8) For good measure, wrap foam tape around the plastic harness that cbettin highlighted in this thread where it makes the 90 degree turn on each side of the inner fenders. (There is a circular plastic retaining clip that I lined with foam.)
9) Enjoy your creak-free 4Runner.
So... if you are still reading... here was everything I went to to get here...
Purchased a 2016 Limited in January of 2016. This was my 3rd 4Runner and the third one from this dealership. I work for another store in the dealer group (at one time was employed by Toyota), so you'd think this would have been an easier process than it was. Unfortunately not. Exact timeline is unsure, but here's how it went.
Purchase - Buy a 2016 Limited to replace a 2015 Limited. Had been driving 500 miles a month for work and wanted to get one with lower mileage after being relocated closer to home. 2015 had the same tick/creak but never really worried much about it because I knew I would trade it in. Drive the 2016 about 100 miles before the same windshield tick occurs.
Dealer Visit 1 - Advise dealer there is a tick from the windshield. Give super descriptive information (including speeds, temperatures, area of the windshield, driving patterns to duplicate, etc.) Advise dealer DO NOT remove the dash without my authorization. Technician calls that afternoon and says its figured out and fixed. Delivers vehicle back to me. Tick still present. Tech says drop it back off for the next day.
Dealer Visit 2 - Drop vehicle off next morning and wait for a call. At 5pm, no call, so I call dealer who advises that technician is off today so no one worked on it. Take a rental home and they will look at it the next day. Next day arrives and technician calls me in late afternoon to tell me it is fixed. Delivers vehicle down to me where the A pillar is covered in grease. There is now a noticeable gap in the dash near the a pillar as well as a bulge in the center of the dash at the base of the windshield. Technician says its from all of the noise insulating foam, but nevermind the look of it, the noise is gone. Technician had removed dash without my authorization (I'm a firm believer that once a dash comes out of a car it will NEVER be the same.) No problem, take vehicle home... noise still there.
Dealer Visit 3 - Drop car off at dealership again, request that a team leader (experienced technician) look at vehicle. That afternoon, same technician from before calls and asks if I'd like to ride with him because he thinks he has fixed the noise. Picks me up in vehicle with dash completely removed. Test drive together and noise still apparent. Requests I leave it overnight as an DTS (Dealer Technical Specialist) will be at dealership the next day for another vehicle and can look at it. Drive rental home. Hear nothing the next day, call to check and am told "DTS was here but didnt look at it. Technician was off today and didnt do anything with it. He'll be back tommorow and can put it back together and reschedule for DTS to look at it." Next day, tech comes in, brings car back (noise still apparent) and now there's an electrical interference noise when gas is applied. Tell dealer to let me know when DTS can look at it. Leave to go home and headlights dont work. Take vehicle back so technician can plug them back in where they were disconnected from dash. (Week later realize auto-headlights dont work either.)
Dealer Visit 4 Drop vehicle off so technician can remove dash for 4th or 5th time to hook up auto headlight sensor in dash that was left unplugged. Noise still very apparent upon return and new noise (electrical interference) promintent.
Weeks go by...
Dealer Visit 5 - After some not-so-pleasant calls and emails to the higher ups in our dealer group, DTS is scheduled to come and look at vehicle. I'm told he had been out about a week earlier and no one let me know. DTS advises "no problem found" on either noise.
Buyback Attempt - Pissed off about having a brand new 2016 with less than 1000 miles on it and a noise from the factory combined with a new noise and the dash being torn out of it, damaged while serviced, etc. I request that the dealer (not Toyota) take this vehicle back and put me in another. Dealer says thats not possible, etc. End up paying difference to trade out of vehicle into an identical one. Pay about $3k out of pocket to do so. Because it is my company, I wasn't going to make a huge stink about it, but hands down I was done wrong.
New Vehicle - Take delivery of another 2016 Limited after test driving and ensuring that this vehicle did not have the tick/rattle in it. Satisfied I take delivery. Approximately 500 miles later, the noise began and has been there since. Technician tightened body bolts from underneath after calling a friend who is an engineer from Toyota and noise seemed to quiet a bit. It wasnt until the last 1000 miles or so (currently have 13,000) that what was an occaisonal "tick" has become more of a constant creak during body flex.
LOOOONNNNGGGG STORY short - after the fix above (at least today) all evidence of noise appears to be gone. If it returns I will post again, but I have been dealing with this for MONTHS with no resolve and the above finally has seemed to fix it.
Its like an itch you cant scratch and finally someone comes along and gets it for you.