Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 20 of 21 Posts

·
Registered
2002 chevy trailblazer_ltz
Joined
·
18 Posts
Discussion Starter · #1 ·
02 trailblazer 4-wheel drive does not want to fully engage sounds like it grinds when I accelerate. Replaced actuator still does the same thing. Now the 4wd switch has begun to blink in all modes and service 4wd light comes on. Any suggestions? Thanks
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
Read up on my many previous posts about how the sounds the two motors make can help you diagnose it. The front axle actuator is a higher-pitched 2-3 second noise and the transfer case encoder motor is a lower pitched and shorter noise.

Grinding is definitely a bad noise. How many miles, and have you ever changed the transfer case fluid?
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
18 Posts
Discussion Starter · #3 ·
It has a 129000 miles never changed fluid. Sounds like both actuators are working.Seems like it is not totally engaging the front axle,front tires don't grab in the snow. I'm wondering if it is the engagement clutch.
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
Since the Owner's Manual recommends 50K for the TC fluid, it may be dead or dying. Open the plugs and see what condition it's in, and measure how much fluid comes out. You'll need 2 quarts of Auto Trak II from GM to refill it, and maybe a hose and squeeze bottle to get to the fill hole.

The lights now are probably from the encoder motor binding up when it tries to move the clutch inside the TC.
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
18 Posts
Discussion Starter · #5 ·
The noise sounds like its from the front axle,like it is not engaging all the way. Transfer case sounds fine.no noise.
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
A common problem as it turns out. Cheaper than a TC, at least. Been posted about with pictures, but you may have to search for the thread. The splined disconnect that the front actuator presses on the fork can disintegrate. There is no requirement for relubricating it, but we're starting to think there should be.

Item #56 in this view.

 

·
Registered
Joined
·
7 Posts
Going through this very same problem...but

hey guys and gals,
i am currently going through this very same problem. Heard a noise like a plastic bag flapping underneath but couldn't find it. I was changing my front pads and noticed the drive axle was a little sloppy when I moved the axle from r to l. It appears to have been rubbing up against the 4wd actuator module and differential. I took it in to a GM certified shop and he said the shaft is broken inside and the actuator isn't working verified through the diagnosis computer he used off the OBDII. I'm certain there's more to it but the four wheel drive doesn't work, the axle is shot and something inside is defintely wrong. I've read in the past postings that this is common amongst "us" but the dealer doesn't have any bulletins or corrective actions for it. As in the shell gears i've replaced twice too. I went through the gas tank thing twice also with 108,000. The only thing I've got to say is she's been good to me, I own it and I am not about to get into a payment again if I don't have to. I know that the I-6 will run forever if I let it. I had the tranny rebuilt completely outside the dealer so the sun shell gears won't rupture again. Anything anyone knows that will help me with the F/E 4wd will help. I've read all the previous posting and they've been fantastic help to me. If you've got any questions I've been through them all I bet. Relocated from Jersey to Texas back in '05. Don't really have a need for the 4wd I wish I could just take it out but the re-sale wouldn't be any good.
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
18 Posts
Discussion Starter · #9 ·
Thanks for the info guys I appreciate it. Looks like I'm going to be tearing into the front axle.Sounds like this is a common problem with these. I'll let you know what I find.
 

·
Registered
chevy trailblazer_ls_ext
Joined
·
46 Posts
Greetings:

Looks like when the Trailblazer hit's 100k the driveline starts to act up. Well here is my situation, While driving back home from a weekend trip 175 miles. The " SERVICE 4WD" light came on. Ok granted....I was planning the following month to have the differential oil seals replaced as well as the fluid, and inspect the transfer case as part of my upkeep.

Well after having dinner....I go back to the vechicle start it up and the service light is off.... Looks like a trip to the transmission doctor. Does anyone have a clue as to what $$$ I may be looking at?

Any thoughts would be great....Thanks for any help

2004 Chevy Trailblazer EXT LS V-8 engine
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
Well, the recommended fluid change interval for the transfer case is 50K, IIRC. Not 100 as a lot of folks think before they read the manual. Have you exercised the 4WD system every few months to keep the actuators limbered up? Many folks have flaky switches, and some of them get replaced, and some get better by just using them. I recommend just turning it from end to end 40-50 times with the ignition off.

Then with the ignition on, but the engine off, run the switch through its modes. You need to be in neutral to get into 4LO. Just get used to the sounds of the two motors that run the front axle actuator and the transfer case encoder motor. Remembering the sounds of it when it's normal will help later if you have a real failure.

Don't spend ANY money on a shop diagnosis when it's an intermittent like that. Just exercise it first and turn the switch to clean up the contacts. And let us know if you changed the TC fluid before now.
 

·
Registered
chevy trailblazer_ls_ext
Joined
·
46 Posts
Thanks

Thanks.....I have scheduled all the fluids to be changed out. What I did was put it on ramps and check the connections. Found some crud and cleaned it.

As for the fluids since it's needed will also do the seals on the diff and later on put a new transmission as a good measure. In late July I'm looking to replace the powerplant with a new one. The bottom line is untill Chevy grows a brain and make the SS with a third row seat. I'm keeping my bow tie forever...With the help and support of this fourm I will.

Thanks for all the help guy's
 

·
Registered
Joined
·
7 Posts
100k 4wd problems

I can certainly agree that 100k seems to be the mark. It appears to me know that the actuator module was the first to notice the symptoms that I did not. I too had a service 4wd alert but it too went off and I ignored it from that point on. Several months later I started hearing a sound of like a plastic grocery bag flapping under the truck. I looked and found nothing. I went to change that front pads and noticed the grease and sloppy right half shaft. Took it in to the dealer, 3g's to fix the obvious f/e problem with these things. The intermediate shaft bearing has no serviceability and fails. They don't put any zerk fittings on anything anymore. I've yet to see a lifetime bearing last a lifetime. Anywho, I found a mechanic who did it for $970.00. He was a little bit out of the way for me, about 60 miles away, but well worth the savings. The dealer wants 3g's for the same repair. Good luck with that, you might save a bit by finding it so early. I lost the shaft, actuator and bearing all together because I didn't service it in time. The shaft got so sloppy that it tore up everything within its spinning area:eek:
 

·
Northwest Chapter
Joined
·
11,824 Posts
Thanks.....I have scheduled all the fluids to be changed out. What I did was put it on ramps and check the connections. Found some crud and cleaned it.

As for the fluids since it's needed will also do the seals on the diff and later on put a new transmission as a good measure. In late July I'm looking to replace the powerplant with a new one. The bottom line is untill Chevy grows a brain and make the SS with a third row seat. I'm keeping my bow tie forever...With the help and support of this fourm I will.

Thanks for all the help guy's
Good idea, Im at 103k on my 02 and going to do the trans, both diffs, and transfer case as soon as I have some time at home, so probably mid-May.

Why would GM make a high performance SUV with 3 rows of seats? The LWB models dont handle as well as SWBs so making an LWB an SS isnt that great of an idea...

If you want it, just put a 6.0L block in your EXT when you replace the motor. Then build the trans and rear end then do the brake and suspension work. Voila, LWB SS.
 

·
Registered
chevy trailblazer_ls_ext
Joined
·
46 Posts
The question is why not? Think about it.....for a moment. Take a 2004-2006 EXT. and beef up the powerplant.....Naturally add performance suspension & brakes and you have a mind blowing monster. The simple fact it can be done.... Now getting the $$$ is another thread.

As for the 4x4 issue well in another thread I will detail the overhaul...
 

·
Registered
chevy trailblazer_ls_ext
Joined
·
46 Posts
Hey Guy's.....I saw this in another fourm. Let me know what you think?




Have you had your transfer case control module reprogrammed with the update? If not, take it to the dealer and refer them to this bulletin.




Bulletin No.: 02-04-21-006E

Date: July 20, 2006

TECHNICAL
Subject:
Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System, DTC C0550 Set, No Communication with TCCM (Reprogram Transfer Case Control Module)

Models:
2004 Buick Rainier
2002-2004 Chevrolet TrailBlazer, TrailBlazer EXT
2003-2004 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2002-2004 GMC Envoy, Envoy XL
2003-2004 GMC Sierra, Yukon, Yukon XL
2004 GMC Envoy XUV
2002-2004 Oldsmobile Bravada

with Electronic Shift **or** Active Transfer Case (RPOs NP1, NP4 **or** NP

Supercede:

This bulletin is being revised to add Subject information and change the labor operation. This bulletin cancels and supersedes Bulletin Number 03-04-21-006. Please discard Corporate Bulletin Numbers 02-04-21-006D and 03-04-21-006 (Section 04 - Driveline/Axle).

Condition

Some customers may comment that the 4WD/AWD indicator lights on the selector switch do not work, **or** the 4WD/AWD system may be inoperative and/**or** the service 4WD light is illuminated. The condition is typically intermittent and always occurs at key-up. Upon investigation, the technician may find DTC C0550 set.

Cause

The Transfer Case Control Module (TCCM) has not received the wake-up call during key-up and has remained in the "sleep mode".

When the TCCM is in the "sleep mode", it will not communicate with the class II bus **or** the Tech 2(R).
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
18 Posts
Discussion Starter · #17 ·
Sounds like this is a common problem with trails. I also have a 2001 yukon,never had a problem with it. I'm starting to wonder if I made a mistake switching to a trailblazer. I think the drivetrain in the yukon is alot tougher. Hope you can find the problem with yours,I'm still working on mine.
 

·
Registered
chevy trailblazer_ls_ext
Joined
·
46 Posts
No not at all you made no mistake in the switch..... This can happen to any vechicle. Just have to bear in mind that as a owner you need to keep your vechicle in tip top shape.

My problem was a low cost fix, Reason being the GM Transmission system is quite avanced, Reason to help the owner detect problems befor they become a big pricey issue...
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
18 Posts
Discussion Starter · #19 ·
I took the engagement clutch assembly out and took it apart.

The outer bearings were bad and the the gear was scored. This assembly had never been apart and the outer bearings had no grease in them from the factory.

I found a used assembly from a junkyard, only had 30,000 miles on it. I decided to pull it apart and check it before I put it back in,guess what, no grease in the outer bearings, so we pulled assemblies off of three other trailblazers,same thing no grease in the outer bearings. All of these had the same problem and the surface where the bearings rides on were scored. Looks like GM never packed the outer bearings on these. Everyone we took apart and checked had the same problem.
I think alot of trails are going to have the same problem.
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
Thanks for the report!! Scary. Seems like we should add a grease packing process to the recommended maintenance list, especially for new owners. Since GM will never tell us about this, if they even know, that's the power of trailvoy.
 
1 - 20 of 21 Posts
Top