Offroad Trailblazers and Envoys

4wd, a4wd and more

Something not working right?

by shesmeanandgreen » Sat Mar 16, 2019 8:15 pm

I'm new to the forums and all that jazz. I've been modifying and caring for my 03LT for 2 years now that I bought off a 90 year old woman that was all stealership serviced. I just recently last year started offroading and getting a feel around the Rockies and Colorado.

Recently I've been trying some snow wheeling and I have some questions for you experienced folks. I've read about the "50-50" torque split over and over and I just dont get it. For instance I got pulled into a snow bank while using 4hi, not a4wd or 4lo, and couldn't get out for the life of me, after gently massaging it and sliding into a Bush I got out. I used 4hi 2hi and 4lo with no difference in wheel spin. I definitely saw the rear end lock up both wheels spinning but nothing from the front, low rpms or letting it rip made no difference, I installed the g80 myself (college student on a hard budget) and it's been okay so far locks up when I want it to. I'm wondering if the Tcase is doing what it's supposed to. Or if it's supposed to act as a center locker.
However when I put into a4wd it got out.

Shortly after this trip I was on my way down from the mountain and while trying to speed up on the bottom of a 5 mile grade the rpms shot up with no dice I pulled over shut it off,turned it on, abs came on and didnt turn off till I got moving again, just flushed the brake system. I only got moving again when I put it into park it made an odd grinding sound so I threw it into neutral and threw the tcase into neutral and back into 2hi this time it got moving. I also used the may03lt method to flush the tranny and it looked immaculate. Both front and rear diffs have had fluid changed.

Thanks for reading sorry if it was long and thanks for the help if you can.

:flex dirty:
shesmeanandgreen
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Name: Micah
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DriveTrain: 4WD

by Trail X » Mon Mar 18, 2019 1:25 pm

Sounds like the transfer case motor lock isn't engaging.

Time to do some reading. Start here, this is the article for diagnosing 4WD issues: http://offroadtb.com/diagnosing-the-4wd-system/ Based on what you said, if you follow the flow chart, it should point to a transfer case problem. At least, I'm about 95% sure... don't just trust me here, follow the flow chart to a T. Please note, there's a chance you will get an outcome that your 4WD is working fine... this is because of a dragging clutch in the transfer case. Sometimes the clutches will retain a fair amount of resistance, but not enough to hold back thousands of pounds of tire force from the engine. Try to apply more torque to the tire during the test. Any torque you can apply will be less than what the drivetrain can handle.

For more information, start reading here. Read it all.... but in particular, try to understand how the motor operates in relation to the transfer case motor lock. http://offroadtb.com/transfer-case-oper ... g-226-np8/

You probably need a new transfer case motor. If you know someone else with a 4WD trailblazer, see if you can temporarily swap transfer case motors and perform the flow chart test again - or go get stuck again.

The transfer case motor lock doesn't really affect 2WD mode, because the rear tires aren't ever controlled by clutch pressure, they have splines holding them in place - but there is a potential for 2WD to disengage once the transfer case motor lock gets worn enough.

Hope this helps.
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by shesmeanandgreen » Mon Mar 18, 2019 5:16 pm

Thanks for the reply, I just looked at the flowchart right after uploading this, I will follow it when I can jack it up. Thanks again
shesmeanandgreen
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Posts: 2
Joined: Fri Nov 03, 2017 11:34 pm
Location: Colorado
Name: Micah
Vehicle Year: 2003
Vehicle: Chevrolet TrailBlazer
DriveTrain: 4WD


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