I have a 2002 TB LT. As long as I can remember the 4x4 has only worked while driving. That is to say if you were in 2 wheel drive and got stuck, you would remain stuck no matter what. Won't go into 4x4 . The vehicle has to be driving down the road to actually go onto 4x4. I have checked with vehicle not running and both differential and encoder motors are working. Not sure if transfer case is problem..or something else. Anyone?
NEED HELP 4x4 Working strange
- Thread starter Sn1perdeath
- Start date
But the TCCM is controlling everything and my switch is working as it should. I also have no service 4x4 lights.
Can you elaborate on "won't go into 4WD" ??
Exactly what mode do you try to go into, 4Hi?? And exactly what happens? What do you see?? What light blink?? For how long?? Then what happens??
Related question: do have a locking rear axle?
Have you followed the 4WD troubleshooting guide??
Ok so just what I said. Switch works as it should. Shift from 2 to anything...Auto..4hi..even in neutral and 4lo. Light blinks momentarily and then stays lit in gear you select. No funny business. You hear the whirring of the decoder motor under and also for a second the one on passenger side of diff. My son is with me for this. There is no clunk or thud of a transfer case that I am used to in my truck. But....it isn't in 4x4 unless you are actually moving. I don't know how to explain it to you if you can't get that. In winter, you drive away in 2wd and drive in deep snow, get stuck, put in 4x4, says you are but you aren't. But if you drive away put in 4x4 and it's driving for some reason traveling is engaging the front wheels. And it is a G80 rear
I have no ideas at this point. Lost. Don't know if I should hear the transfer case clunk or is it a problem with the disconnect in the front. I'm just confused. It's not giving any codes.
freddyboy61
Member
- Dec 4, 2011
- 276
One thing I can think of, maybe the front disconnect is not engaging from a stand still condition, but will engage while things are moving. The disconnect is known to be poorly lubricated.
Agree with freddyboy61, sounds like a lubrication issue. Following link goes into good detail: https://offroadtb.com/4wd-disconnect-rebuild/
flyboy2610
Member
I recall reading somewhere of one guy who drilled and tapped the front disconnect case for a grease fitting.Gives it a few pumps of grease occasionally. I'm seriously considering doing the same thing.
So if this is the disconnect, will other years fit? So I can take another to rebuild just so I have less down time on mine. This would be great.
Before heading out to pickup parts you first have to validate (or refute) the working hypothesis that this is a lubrication issue. Beyond some additional inspections you could perform like raising the right front wheel off the ground and listening/feeling while exercising the disconnect as you rotate the wheel, final determination is going to involve pulling the part and inspecting the condition of the internal components. A video with good details on getting at the disconnect:
Sure will. Won't be for a bit. Probably a couple weeks before I take it apart but I will certainly show the catastrophic details. Lol
This thread is a good incentive for others to inspect the internals of the disconnect, even if you are not currently having a problem. After hundreds of thousands of miles and decades of use the grease hardens, seals fail and bearings wear. So you could wait like the OP for a catastrophic failure before doing anything - or - pick some boring afternoon and remove the disconnect for an inspection. It's a known failure point, and you can eliminate the uncertainty.
Mooseman
Moderator
I almost was going to reply back to you that you might have some internal damage in the front, but wasn't sure and just felt like a guess. I know exactly what you are talking about, I had a jeep that did this and it's maddening. Put it in 4W, and doesn't go in unless the vehicle is rolling along. Pretty much useless in a "stuck in the snow" environment. I can clearly remember just sitting on my driveway which had a little ice on it, nothing more, and being stuck, put it in 4w, had no effect on driveability. No warning lights, no codes, but the vehicle said it was in 4W just fine.
Here's what the grease looked like in mine:
Definitely needed a repack. Fortunately there was only minor wear and only the outer seal required replacement.
Definitely needed a repack. Fortunately there was only minor wear and only the outer seal required replacement.
In order for 4x4 to engage your trailblazer will need to be moved a little bit and turning your wheels. This is due to the 4wd disconnect not being able to mesh with the front differential intermediate shaft. This is perfectly normal. If you are stuck and in 2hi then turning your wheels left and right with some jolting from the rears tired should lock the gears in place and engage 4wd. If you were to take apart the 4wd disconnect on the passenger side you would see what I mean.
I definitely can live with the ticking. It's actually improving since I've been running the fresh Mobil One. Thank for the info.
Once you get it fixed and back into the vehicle when you know you will need 4wd I suggest to move at a crawl with some turning. Once it kicks in then drive normal. Try not to use the a4wd. Just stick with 2hi,4hi,or 4low. In a4wd the front is running maybe 5-10% engaged and then when it feels slipping the computer will give the front full power. This can actually hurt the aluminum fork.
Quick update. I have been trying out the rislone engine treatment my last two oil changes. Bottle says one bottle good for 5quartz and our engine calls for 6.9 quartz. So I also threw in half a quart of trans fluid. It did quiet my noisy lifter for a while, maybe for 3000 miles then started again. I just did another oil change with same routine and it has actually gotten a little better than last time. Im not saying it's an actual fix but do notice it being not as noisy. Maybe you can try it to see what it does for you. It's available at Walmart and AutoZone. If I can remember next oil change with same routine then add an update if it's near same or if it's better. Obviously real fix is to replace lifters but still worth a shot