Auto 4 wd on 2003 trailblazier is not cutting off.

check that the actuator is moving the gear dog into position fully for complete engagement
it indicates that the connection is not complete and the pressure on the teeth is making if jump out of the engagement
have an accredited transmission shop check that adjustment
the symptoms indicate a failure to properly engage --adjustment--or worn teeth of the dog--- new parts -- or misalignment of the shafts --- new bearings and parts
have a proper diagnosis done first as replacement parts gets to be an expensive job

You wasted your time at Advanced Auto --because they
won't explain what needs to be done & you wouldn't understand
anyway

Go to a repair shop--they have to use the proper professional
scan tools & testing procedures, along with reference material

It has to be component tested

This procedure has been with us for 32 years now,
any time you get any dash lights or codes

bring it to an auto parts store-they can help titen it at the tensioner--may need a new one

there should be a door sticker that says this, or call your toyota dealer and give vin # if needed

There are any number of commercial protection products available over the counter.. of any auto part store, or online.

In my own humble opinion... Your best protection is regular washing with clean water, and some WD40 on all unpainted surfaces. Any coating you put on will eventually trap moisture and contaminants under it, causing corrosion faster.
Easy way to prevent undercarriage rust is to power wash the entire undercarrage, then spray the entire undercarriage with WD-40 before the onset of winter.

WD-40 displaces water, helping to keep rust under control. Suprisingly, it doesn't come off as easily as you'd think in wet winter driving.
Use use two medium size cans of WD-40 to do all undercarriage, making sure to spray every nook and cranny (but avoiding the brake rotors/pads) until it is saturated.

Believe it or not, one good coating will last all winter--at least enough to prevent rust. Each spring, use a high pressure sprayer to clean the undercarriage and reapply a new coat of WD-40 for the spring/summer/fall months.

Auto 4 wd is when the Silverado's PCM takes readings from the front and rear driver shaft and when there is any detection that the speeds are different. The Auto 4WD will activate the transfer case to lock it self to 4wd until the front and rear drive shaft are running at the same given speed of rotation.

Thank you for using fixya

Well we don't know what size engine your vehicle has or weather it is a auto transmission or manual but here are the capacities.
Auto transmission
4 speed- 4wd 7.5 quarts
4 speed 2wd 7.8 quarts
Manual transmission 2 wd 4.0 quarts
Manual transmission 4 wd 3.2 quarts

this information is for 2.0L 4 cylinder engine code (C) DOHC
if you need information for 1.6L then send me a message back and I will give you the info.

Sounds like you have a bad bearing hub (likely in front but you need to determine which side) You really can't tell by shaking it, unless its falling apart. Remove front brakes and rotors and turn the bearing by hand, any slight roughness is a problem (you can't exert as much force as the vehicle weight of the vehicle)

hi how are you. your auto choke is bad will need to replace.depending on wich one you have it may only be the vacume choke diafram ( high idle cut off). or it is the electric choke