# Damage to vehicle if switch from 2WD to 4AWD while vehicle is stationary?

**URL:** <https://community.cartalk.com/t/damage-to-vehicle-if-switch-from-2wd-to-4awd-while-vehicle-is-stationary/89079>\
**Category:** General Discussion\
**Created:** [February 18, 2015, 8:28am UTC](https://community.cartalk.com/t/damage-to-vehicle-if-switch-from-2wd-to-4awd-while-vehicle-is-stationary/89079 "2015-02-18T08:28:17Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![brideofbonehead](https://avatars.discourse-cdn.com/v4/letter/b/46a35a/32.png) [@brideofbonehead](https://community.cartalk.com/u/brideofbonehead)\
**Post date:** [February 18, 2015, 8:28am UTC](https://community.cartalk.com/t/damage-to-vehicle-if-switch-from-2wd-to-4awd-while-vehicle-is-stationary/89079/1 "2015-02-18T08:28:17Z")

</div>

Hi. Newbie here. Is it possible to cause damage to a vehicle (2003?? Chevy Trailblazer) with an on-the-fly 2WD to 4AWD system by switching to 4AWD when the vehicle is in park or otherwise not driving forward? This was done by someone and now the vehicle is making a loud noise.

---

<div class="post-metadata">

**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\
**Post date:** [February 18, 2015, 9:12am UTC](https://community.cartalk.com/t/damage-to-vehicle-if-switch-from-2wd-to-4awd-while-vehicle-is-stationary/89079/2 "2015-02-18T09:12:19Z")

</div>

What’s your owner’s manual say?

---

<div class="post-metadata">

**Author:** ![TwinTurbo](https://avatars.discourse-cdn.com/v4/letter/t/8baadc/32.png) [@TwinTurbo](https://community.cartalk.com/u/TwinTurbo)\
**Post date:** [February 18, 2015, 10:17pm UTC](https://community.cartalk.com/t/damage-to-vehicle-if-switch-from-2wd-to-4awd-while-vehicle-is-stationary/89079/3 "2015-02-18T22:17:24Z")

</div>

You can switch back and forth from 2WD to A4WD or 4HI while moving but you must be stopped to select 4LO. You can select any mode while stopped although as long as I’ve owned Chevy’s I purposely make sure the steering is pointed straight ahead when making changes as it seems to put undue stress on the actuator(s) the further the wheel is cranked to a side. I suspect this is what was done to your truck.

The Automatic 4WD option on the TB is one of the most convenient and well implemented features I have ever had. It’s in 2WD until it senses slippage and automatically applies 4WD. Until then there is no turning bind and no friction loss. Super convenient for plowing residential driveways or other tight radius operations in slick conditions…