Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

1 - 7 of 7 Posts

·
Registered
2002 chevy trailblazer_lt
Joined
·
1 Posts
Discussion Starter #1
my wife recently reported to me, while driving in 2hi the light above 4hi is lit up and the light above 4lo is flashing. that didnt alarm me much since we have two toddlers i assumed one of them bumed the switch and it was trying to engage after the fact, i had her pull over put in N switch to 4lo then to 4hi then to a4 then 2hi, just to cycle the transfer case. however when pulling into or out of a driveway or parking space it will intermittently bind up like its in 4lo then after a few moments clunk hard upon what seems to me to be 4lo disengagement. that has happened to my wife a couple times, so upon HER description of the issue i put it on the lift and pulled all the wheels all the calipers and all the pads which are and were almost new. after throroughly checking drivetrain i put it back together and decided to drive it for a couple days as the problem is very intermitent. my first and only experience with the problem was backing out of a parking space, the wheels bound tight, i gently powered through it, wheels chirped and acted like 4lo, switch still in 2hi, dry conditions, drove aprox half mile to next store, truck felt a little weird while pulling into store lot when i noticed the lights were lit as when my wife told me they were when she was driving down the highway days before... switch in 2hi, light above 4hi lit steadily and light above 4lo was flashing. then huge disengagment clunk, weve only had the truck a short while. after i pulled it off the lift the day before, i engaged disengaged and tinkered with 4x4 for several minutes to look for issues since my thought was if i cant find anything with the wheels maybe the lights she described days before were a clue. point being it was very smooth and quiet when in the shop, and all did work properly.. today( a day after i wrote this) i was driving in town 35mph, and i watched the 4x4 indicator light shift itself into A4x4 i hit a stop light almost imediately so i put truck in N and shifted through the gears in the transfer case, didnt act up again.

sorry for the novel but im trying to be a specific as possible, im guessing this may be a bad switch? had seen similar problems online while searching and they say tccm? but havnt seen any of the exact problem upon searching. dealership said today they are thinking encoder motor sensor, but they also said they were unaware of any historical problems with 02 4x4 systems, from what ive researched i should have laughed in their face. side note, truck 100,000 miles and an I6 2002 LT and NO service 4x4 light came on

thanks for your help!
 

·
Registered
2002 chevy trailblazer_lt_ext
Joined
·
3 Posts
Any new info for this?

Does anyone have any more info on this issue? I also have an '02 4x4 that binds up during low speed sharp turns. The service 4x4 light comes on, but its gone by the next start up.
 

·
Registered
2008 gmc envoy_sle
Joined
·
579 Posts
welcome to the site

while we wait for someone with more knowledge on the four wheel drive system to answer this post.

lets start with the obvious.

have you checked the 4x4 switch, the TCCM and the transfer case motor?

start with cleaning all connections to the above components.
 

·
Registered
2002 chevy trailblazer_lt_ext
Joined
·
3 Posts
welcome to the site

while we wait for someone with more knowledge on the four wheel drive system to answer this post.

lets start with the obvious.

have you checked the 4x4 switch, the TCCM and the transfer case motor?

start with cleaning all connections to the above components.
I haven't had time to really check much of it out. My wife drives it everyday, and there hasn't been much free time lately. The problem is very intermittent, but I am trying to get ahead of it. There is a bulletin in GM Service Information about replacing the sensor on the encoder motor. The bulletin also says to reprogram the TCCM after replacing the sensor. I am going to start there. I work in parts at a GM dealer, so the parts are readily available, and at a discount. I just wanted to see if anyone had fixed the issue. Those bulletins from GM aren't fool proof.
 

·
Registered
Joined
·
25 Posts
I had a problem with speed sensor on tc causing a4x4 to malfunction causing lots of problems. I hooked it back up and it dixes that problem.
 

·
Registered
2008 chevy trailblazer_lt
Joined
·
1 Posts
Hey y'all... I'm having the same issue on my '08 TB LT... I'll take it 1 step farther tho... I was getting on the interstate at approx. 50mph and climbing, and that's when the ghost in my TB decided to switch it into 4HI... Luckily it didn't kill anything. I pulled over and cycled thru all the modes and everything worked as it was supposed to. Occasionally the service 4WD light or service Stabilitrac light comes on.
 
1 - 7 of 7 Posts
Top