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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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2008 Chev Trailblazer- Clicking noise in front when engaging

Customer Question

2008 Chev Trailblazer- Clicking noise in front when engaging 4wd. I replaced the actuator and still have a problem. I assume the problem is what the actuator is working inside, maybe a shifter or gear that is not allowing the shifter to engage?
JA: How old is the transmission? Have you checked the brake switch?
Customer: 61000 on car and it has been used only on main roads. Brake switch- no
JA: Are you fixing your Trailblazer yourself? What have you tried so far?
Customer: Yes.explained about the actuator (front). the transfer case actuator is working- front driveline does turn. Front wheels are not turning in 4wd and actuator does sound like it is engaged. I did replace it
JA: The mechanic is ready to answer your Trailblazer question. Is there anything else you want him to know?
Customer: I guess not
Submitted: 1 month ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 month ago.

HI there, I am Cam.

On your vehicle, this is the front axle actuator you are talking about? Was it the small black actuator you replaced or the larger assembly the actuator attaches to?

Customer: replied 1 month ago.
Just the actuator. I test drove the car after getting it off the jack stands and everything is working ok. While on the stands when I tried to switch to 4wd Hi, the area where the front actuator is made a loud clicking noise and the front wheels didn't turn. Maybe with the angle the wheels were hanging in- fouled up the actuator being able to work. The front driveline was turning. I still have a different feel to the front end. I describe it like running aggressive tread tires. I will check front wheel bearings next. The 4wd is working in hi range and low range.
Expert:  GM Tech (Cam) replied 1 month ago.

I thin your issue its the front axle actuator assembly, not just the actuator, but the sliding gears and such inside. The system will work even with the wheels hanging.