Yet another Trailblazer 4 wheel drive problem thread.

[Ejshepherd]

Hello everyone

I found my way here reading threads about Trailblazers and found that it seems the best experts including "the roadie" actively posts here. This being said here are my issues/concerns.

I have a 2005 trailblazer ext lt 4.2 engine with 175,000 miles on it. I just purchased it a week ago so I have no maintenance records to share with you. I have read that changing the transfer case fluid is vitally important for these vehicles and this will be one of the first things that will be done next week when I take it have some work and service done on it.

I have not been able to do most of the tests suggested

Offroadtb.com Diagnosing the 4WD System

It is to cold here snow/ice ever where and I have no place to get my trailblazer inside to do these tests.

I did pull fuse #8 and this made no change.

I have read many threads on the 4WD lines of these vehicles and I am not a mechanic and certainly not a expert but I have tried to educate myself the best I could before making this post and I will try to provide as much information I can so the members of this forum can provide the best feedback/suggestions possible.

I have no warning lights of any kind. I had onstar run their diagnostic and there was no issues found. I am sure this is less than ideal as far as system checks go but its what I have at my disposal right now.

When I select 4WH the light flashes then goes solid but the 4WH is not working.

When I select AWD the light flashes goes solid and if traction is lost the AWD in and starts pulling. I have much snow to run this test in. One thing I did notice about the AWD when the AWD has been engaged and under "load" everything seems fine, but when it isn't under load and only after it has been engaged it feels like it is kicking in and out of AWD mode a few times and then everything seems normal.

When I select 4WL the light flashes and will not go solid for 4WL it goes back solid on whatever I had selected before.

Now I thought I had sorted the problem out from reading many threads till I realized the 4WL was not locking. I thought the problem was/is my transfer case encoder motor/actuator and a fluid change. Now after seeing that the 4WL will not engage I am not so sure. At this point I am deeply concerned I may have bigger problems.

I have ordered

ACDelco 89059275 Transfer Case Four Wheel Drive Actuator : Amazon.com : Automotive

At this point I am not sure this is going to fix my problem. I will also be changing the transfer case fluid first to see what kind of condition it is in. I do have one question that should be easy enough to answer. Where do I get the transfer case fluid other than a GM dealer? If I have to go to a GM dealer I will I was just wondering if there was any place else that carry's it? I tried AZ, Advanced, and O'reilly's they don't seem to have it or a compatible fluid. I wish I could provide more information since I am asking for help but this is all I have. But please do feel free to ask me questions and I will answer them the best I can!

Thanks for your time and reading my thread!

Joe

 

[IllogicTC]

I typed in "auto trak ii" on Google and my top result was a hit for O'Reilly, selling at $8.99/bottle around my area. Summit Racing sells it for $7.97 a bottle. You'll need two to complete the change. If you weren't so pressed for it, you could just search "GM 88900402," which is the part number for Auto Trak II, and get it off GMPartsDirect for $5.41 a bottle, though their shipping times may not meet the expediency which you may require.

Wherever you choose, make sure it's a bottle with the GM logo on the top-left of the label. I wouldn't even trust the AC Delco bottles and I definitely wouldn't trust any supposed substitute.

When going your transfer case, you'll need either a 10mm hex bit or allen wrench to pop the drain bolt, in addition to your fluid, and you'll need a pump or turkey baster or something to get the new fluid in through the fill hole. If any weird crap comes out with the old fluid, I can probably tell you what I think is happening. The old fluid should either be blue, or look a bit like old dishwater at max, if it's anything else it was long overdue and I would kick the former owner in the head over it!!!

 

[Ejshepherd]

I typed in "auto trak ii" on Google and my top result was a hit for O'Reilly, selling at $8.99/bottle around my area. Summit Racing sells it for $7.97 a bottle. You'll need two to complete the change. If you weren't so pressed for it, you could just search "GM 88900402," which is the part number for Auto Trak II, and get it off GMPartsDirect for $5.41 a bottle, though their shipping times may not meet the expediency which you may require.

I think I will call around to the local dealers and see if I can't find the fluid from them. Thanks for the info!

If any weird crap comes out with the old fluid, I can probably tell you what I think is happening. The old fluid should either be blue, or look a bit like old dishwater at max, if it's anything else it was long overdue and I would kick the former owner in the head over it!!!

Weird crap I would assume means some sort of internal failure in the transfer case. Is that a safe assumption?

Again thanks for your input and time!

Joe

 

[IllogicTC]

It MIGHT mean a failure, depending on what it looks like. It could just be extraordinarily old and chunky like curdled milk, who knows?

 

[Ejshepherd]

It MIGHT mean a failure, depending on what it looks like. It could just be extraordinarily old and chunky like curdled milk, who knows?

I understand what you mean. If I can get my hands on some fluid tomorrow I will see if I can get it changed. This will give me some answers. I am not going to panic even if it is a transfer case failure. I purchased this Trailblazer for a really good price and from what I am seeing online I can get a used replacement for a rather reasonable price. I will update as I get more information just to let everyone know what I have found and hopefully anything I learn and share here maybe able to help someone else out in the future! Thanks again IllogicTC for responding.

Joe

 

[IllogicTC]

Don't be afraid to take pictures of the fluid or the transfer case or step-by-steps on how to do some maintenance item you're doing... we love cataloging and we love information

Seriously, let us know how this all goes. I'm not the resident 4x4 expert, the knowledge I have is mostly second-hand from observing other threads, but I do try to point people in the right direction at least. If you can at least get photographic documentation of the condition of the old fluid, and of anything that may come out with it if it's going to be that way, it may aid one of the 4x4 gurus in assisting you with what to do next.

And I'll save The Roadie a step and mention the transfer case has a relatively short fluid interval at 50,000 miles, and it is heartily recommended that this standard be adhered to very strictly. If the previous owner(s) never touched it, this could mean big trouble, but we don't have that information, so the next best thing is to try gauging it off the condition of the old fluid.

If it's necessary to replace the transfer case, definitely look around, if you can find a nice one at a pull-a-part or something, it'd save you a ton over paying $1400-1500 (at the GMPartsDirect discount rate even) for a new/reman one. Make sure if you get a new one to replace the fluid as soon as it's mounted up (on level ground the fill hole acts as an automatic fullness indicator, if it comes out it's full ). You may be able to sell off your old one to be remanufactured/rebuilt/whatevered but I'm not sure on any specifics on looking into that, otherwise maybe dissect and learn a thing or two about the innards and hold on to any key parts that are in good condition just in case

 

[freddyboy61]

You do realize that in order to go into 4LO the transmission needs to be in Neutral and you may have to let the truck move slightly.

Also, before you drain the transfer case fluid, make sure you can open the fill plug, otherwise you will be up the creek in trying to put new fluid in it.

Good luck

 

[IllogicTC]

You do realize that in order to go into 4LO the transmission needs to be in Neutral and you may have to let the truck move slightly.

Also, before you drain the transfer case fluid, make sure you can open the fill plug, otherwise you will be up the creek in trying to put new fluid in it.

Good luck

Shoot, good point good point good point!!! Yes!!! Have you made sure you're in neutral and under I believe 3MPH (according to the manual, I'd rather do it stopped if possible) when attempting to switch to 4LO? I believe there's a safety interlock to ensure it won't attempt engagement unless it's in neutral, but the speed thing you're accountable for. I'm not sure if the light would continue flashing before returning to its previous state, continue flashing indefinitely, or flash and then turn off when the interlock fails its check.

 

[{tpc}]

Seems odd that the AWD works and the 4 hi doesn't. I think the 4 lo might be because of the neutral thing, so interested if it really was attempted while in neutral.

I am the furthest thing from an expert but it sounds to me like the AWD is working as designed? My thought of how that worked was that it only engaged when it felt a loss of traction? At least that is how our envoy works. When the weather is like it is, I use the fact that they are horrible in plowing our street to put it through its paces.

My wife says she did have an issue with the engagement of the AWD/4WD system a few years back, and had the dealer fix it. I slightly remember this, but being how its her car I let her deal with it (I'm guessing actuator problem since she said it wouldn't engage). Of course I am hoping they did a fluid change on everything back then....as I am unsure if I can find the paperwork, and I think the dealer she normally dealt with is out of business now.

The reason I am here now is that we plan on using this truck more like a truck and less like a daily driver, and I'll be doing the driving, so I need to be involved lol. Plus she wants to drive it as her daily a bit longer.

 

[The_Roadie]

Seems odd that the AWD works and the 4 hi doesn't.

Many of us on ORTB were mystified by the same behavior, and when changing the encoder motor started fixing these things, we deduced it had to be caused by dead brake solenoids in the encoder motor. In A4WD mode, the TCCM is constantly adjusting the clutch position by movement of the encoder motor so the brake has to be off. In 4HI, we think the TCCM sends the encoder motor to a fixed position that engages the clutches, then sets the brake, and then quits looking at the shaft position. Without a working brake, we think that's how the TC starts slipping in 4HI mode.

I am the furthest thing from an expert but it sounds to me like the AWD is working as designed? My thought of how that worked was that it only engaged when it felt a loss of traction? At least that is how our envoy works.

That's the behavior, all right.

 

[Ejshepherd]

Well its to cold outside yet again and I stopped by a couple of our local small shops and they had vehicles on their lifts so I was not able to get them to look at it or let me use a lift. I am good friends with the one guy and if he didn't have his two lifts tied up he would have let me used one.

I did find the Auto-Trak II Fluid I needed at the cost of $19.11 with tax for 2 quarts. Not overly thrilled about that but I need it so what are you doing to do? I checked all the local retail auto parts chain stores and none of them carried it.

I now have a new problem. I still do not have any service lights or anything lighting up on my dash. When I went out and started it this morning the selector was in 2WD mode it flashed a couple of times and did not go solid the light just went off. So I tried to select AWD and it flashed a few times and just went dark. It drives fine there has been no grinding sounds clunks or anything at all unusual at all. I did remove fuse #8 it seemed to reset everything and I was able to select AWD 4WD it would flash and go solid in those positions. AWD worked like it has in the past. Just a bit ago I had to take my kids to the bus stop went out and started it and the same thing happened. It was in 2WD position the light flashed a few times and it just went out it would not go solid.

I have no idea if this could be related the transfer case actuator or not. I am at a complete lose at this point and time so I have scheduled it to be looked at by one of my local garages. The first thing he is going to do is change the fluid in the transfer case for me and depending on the condition of that we will make a decision as to what do do next. I will have him take pictures of the fluid I may in fact be there myself at the time since this is the guy I am good friends with.

Anyways thanks for the input guys and if you have anymore suggestions please let me know. You have all been a great help so far!

Many thanks for your time and help!

Joe

 

[Ejshepherd]

Just another quick update. The issue I posted that was happening this morning is no longer happening. I can switch through the 4WD selections and the light flashes and goes solid like it is supposed to. Some of you may call me crazy but I am going to chalk that up to the -15 degree temps this morning. I know these sub-zero temps can mess with vehicles in weird ways. It messes with my Sierra when it is this cold and turns my tow/haul on and I can not turn it off with my switch or anything. The only way to get it to go off is to let the truck warm up really good and then shut the entire thing off and restart it then the tow/haul is back to normal.

Joe

 

[IllogicTC]

It may be a sign that your encoder motor isn't going to be too far off in the repair/replace list, but at least you know the likely cause, the solution, and that so far it only does it in extreme cold.

The conjecture on how it runs its different settings and sets the brake and whatnot kinda makes me wanna crawl under there with a non-contact sensor. I'm genuinely curious.

 

[The_Roadie]

I'm genuinely curious.

One of the top ten most valuable attributes you can have.

Robert Heinlein:

A human being should be able to change a diaper, plan an invasion, butcher a hog, conn a ship, design a building, write a sonnet, balance accounts, build a wall, set a bone, comfort the dying, take orders, give orders, cooperate, act alone, solve equations, analyze a new problem, pitch manure, program a computer, cook a tasty meal, fight efficiently, die gallantly. Specialization is for insects.

-Lazarus Long, Time Enough For Love

 

[Ejshepherd]

Not exactly a update but I did want to let everyone know that I was having another extremely minor issue that I also have since "repaired" myself and I found the info I needed right here on this forum to take care of it. The folks I purchased my Trailblazer from told me last August they replaced the belt and it had squeaked ever since. Well I found out from here that it was likely the put the wrong size belt on it. That was exactly what was wrong with it, I put the correct size on it and problem solved.

Waiting till my appointment next week to see about the 4WD issues which I am fairly confident that will be fixed with the part I ordered and have since received.

 

[IllogicTC]

Not exactly a update but I did want to let everyone know that I was having another extremely minor issue that I also have since "repaired" myself and I found the info I needed right here on this forum to take care of it. The folks I purchased my Trailblazer from told me last August they replaced the belt and it had squeaked ever since. Well I found out from here that it was likely the put the wrong size belt on it. That was exactly what was wrong with it, I put the correct size on it and problem solved.

Waiting till my appointment next week to see about the 4WD issues which I am fairly confident that will be fixed with the part I ordered and have since received.

The LWB belt's not that old and should still be in good shape, then. If you have any friends with a LWB GMT360, you can save them a few bucks while making a few yourself.

 

[The_Roadie]

LWB GMT360,

Another GM tidbit for the archives. SWB is the GMT360 platform. LWB (EXT/XL) is a GMT370. The totally unique Envoy XUV is a GMT305.

 

[IllogicTC]

Another GM tidbit for the archives. SWB is the GMT360 platform. LWB (EXT/XL) is a GMT370. The totally unique Envoy XUV is a GMT305.

Whoops. 360 sounds better. We're doing circles around some other platforms, or maybe just spinning in a circle trying to fix out 4x4 systems? Put an XBox 360 in in GMT360 and have 360ception.

 

[Ejshepherd]

Well took my Trailblazer in today. My guy changed the transfer case fluid first just to make sure I didn't have a more serious problem, he said the fluid looked fine he installed the transfer case actuator all 4 wheel drive positions work as they should now. Total cost for my repairs was $200 including labor. Not to shabby I got one hell of a deal over all on this Trailblazer and couldn't be happier.