Just purchased an 05 Trailblazer EXT with 170K. Ideas on things to check?

Gearheadvr4

Gearheadvr4

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Just purchased an 05 Trailblazer EXT with 170K. Ideas on things to check?

Do have a service 4x4 light but the 4x4 works. Low on smurf lube for the transfer case maybe?? She runs great and no visible leaks anywhere. No ideas on the maintenance history so I've done a basic tuneup (spark plugs, air filter, oil change WTF 7 quarts!) so far plus transmission filter change. I cleaned the lift gate hinges and lubricated them to prevent rust. Cleaned the throttle body which wasn't too bad. My son cleaned the headlights since they has started to yellow a bit. Lastly had the rest of the kids wash, wax, and detail.

Things to fix that I've seen so far... AC line is leaking out of the service port. It will hold a vacuum but leaks there when charged. Guess I'll need a new line. No idea if you can fix the ports? The blower motor for the AC only has one speed. So I'll need a resistor pack I assume.

I also own an 06 SS so I'm very familiar with the body but the i6 is new to me as is the 4x4.
 

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Welcome to the Nation!

Looks very smart, I wish my engine compartment was that clean.

You're well on your way to doing the routine maintenance. Besides draining and refilling the transfer case you should also do the front and rear differentials. Just make sure you can open the fill plugs first.

Another thing recently pointed out is making sure you can lower the spare tire. There's a secondary safety latch that can become a pain. (Check the tire for pressure while your at it.) That's on my list for today.

BTW it will really help if you fill in the rest of the vehicle info in your profile. Thus if you have a question readers can quickly know what platform you're referring to.
 
Nice looking EXT! For the A/C port, you can replace the internal valve, exactly the same as a tire valve. Just replace it with one for A/C.

For the 4x4, you might need a high end code reader to find out what it causing the light. Did you change the TC fluid lately? (smurf lube, I like that!) Because it was low, hopefully the TC wasn't damaged. The Roadie is THE AUTHORITY on this system so I will defer to him for further advice.
 
Welcome to the nation! Glad to see you made it over. I think you'll find this place much more helpful.
 
On the AC port, it is not a shrieder valve type. It looks like a rubber bulb. Can that be replaced?

I just purchased it 2 days ago so I have no idea on the history of the transfer case. I have a bluetooth ODBII reader. No clue if it can read that code yet. Likely not.

Good idea on the diff. Didn't think to check that. 75w90?
 
Mooseman said:
The Roadie is THE AUTHORITY on this system so I will defer to him for further advice.
Click to expand...
You rang? :biggrin:

Gearheadvr4 said:
Do have a service 4x4 light but the 4x4 works. Low on smurf lube for the transfer case maybe??
Click to expand...
Welcome!

The transfer case doesn't have a fluid level sensor. It REQUIRES changing the fluid every 50K miles. Many, many owners don't know this or are in denial even after reading the Owner's Manual. It's not folklore - the fluid will not last 100K miles, even if they never use the 4WD system. The transfer case guts are always in motion - it's just a set of clutch plates that get engaged in the various 4WD modes.

So definitely measure the amount of fluid that drains out, and note its color and any particles. 2 liters - usually a dealer-only item.

When you say 4x4 "works", what observations specifically do you have? Lights on the mode switch, or a functional test to see if you have traction from the front wheels on sand or ice? Or you observe driveline binding (crow-hopping) when in 4HI mode on dry pavement and turning as into a parking lot space?

A quick summary - A4WD is useless. It's a mode to make soccer moms feel like they have full-time 4WD that they don't have to fiddle with. Not true. It's a mode that waits for the rear wheels to slip, then the transfer case clutches engage and send torque forward until all four wheels are spinning at the same RPM again. The engagement of the transfer case can be abrupt, especially with deteriorated grabby clutches from a neglected TC, and can CAUSE a spinout.

There are two control things going on, and you can listen to them happening and sometimes diagnose problems only by ear. In 2WD mode, the passenger side axle is disconnected from the front diff and that lets both front wheels freewheel and that saves a tiny bit of gas. The thing that manages this is the front axle splined disconnect, and they can go bad mechanically around 100-150K. It is controlled by what we call the front axle actuator, and that makes a high pitched whine for about one second when it engages and disengages. It is disengaged for 2WD mode, and engaged for the other three, so it ONLY makes its noise in the 2HI->A4WD mode transition and A4WD->2HI.

If the front axle actuator fails to complete its motion when commanded, the mode light on the switch will flash for a longer time, and not go steady in the new mode you commanded. That should also set the "Service 4WD" light on the dash.

A splined disconnect that's gone bad mechanically may not set a code, may not flash any lights, and might look as if it's all fat and happy. But it will still fail the functional test and there is a tutorial on rebuilding or replacing them. It'll cost $400-500 for an aftermarket one if you don't rebuild yours, if it fails.

The other noise, a lower-pitched, shorter duration noise, is from the "encoder motor" on the side of the transfer case. It makes a noise in all mode transitions.

A note from the Owner's Manual - 4LO mode has two interlocks so it can never, even by accident, be engaged at high driving speed, which could be fatal. You have to have the tranny in neutral, and you have to be rolling under 3 MPH or preferably stopped.

The "Service 4WD" light also lights up on the dash if the PCM (powertrain control module) loses data communication with the TCCM (transfer case control module), but that happens a lot more on 2002 trucks with the 1st bad GM designed TCCM. Later replacements are OK for the most part. A sure sign of a dead TCCM is that the mode lights on the switch fail to all flash for one second when you first turn on the ignition, during the "lamp test" time that also flashes all the dash lights.

The SS AWD transfer case is different, so don't go by anything you read elsewhere about that system. Have you been on another forum for supporting your SS? Trailvoy is now a virtual ghost town, after we all left there at the end of 2011.
 
Gearheadvr4 said:
On the AC port, it is not a shrieder valve type. It looks like a rubber bulb. Can that be replaced?
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I'm trying real hard to figure out what "rubber bulb" you're talking about. A pic of the offending part would help.
 
Mooseman said:
I'm trying real hard to figure out what "rubber bulb" you're talking about. A pic of the offending part would help.
Click to expand...


It's small rubber bulb instead of a schrader valve.
 

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The_Roadie said:
You rang? :biggrin:

When you say 4x4 "works", what observations specifically do you have? Lights on the mode switch, or a functional test to see if you have traction from the front wheels on sand or ice? Or you observe driveline binding (crow-hopping) when in 4HI mode on dry pavement and turning as into a parking lot space?
Click to expand...


The "service 4x4" light is constant. The selector light on the dash switches and doesn't blink from what I can remember. I can hear the clunk and can hear a difference in the engine load when I engage 4 hi and 4 low and drive with them on. I live 2 min from the beach and could tell a difference with 4 high and low on. Didn't get stuck in the dunes. So it seems to be working but I do not want to continue use and risk damage unless I can diagnose the service light and swap the transfer case fluid first. BTW, crow hopping? explain...

I know little about 4x4 systems other than what the components are and a general idea of what does what. Any help you could provide would be amazing.
 
Pulled two codes for a check engine light this morning. P0113 and P0014.

P0113 - Powertrain, intake air temperature circuit high input

P0014 - Powertrain, "B" camshaft postion timing over advanced or system performance (bank 1)


Ideas?? The idle is a little rough but power seems about the same.
 
FYI, I just rebuilt my disconnect last Fall. From the dealership, all bearings, shims, and seals cost just under $90. For my first-time disassembly (having no previous experience with the 4x4 drivetrain) it took around 2 hours to figure out how to get the disconnect removed from the vehicle, and about an hour to tear it down, clean, and install all the new parts. Pack it with a good synthetic lube, and it was probably only another 30 minutes to put it all back together again.

In my case, I had noticed the previous Winter that my front wheels were not engaging all the time. On dry pavement it felt like they were pulling, but when I got into snow there was no doubt I wasn't getting power to the front. I guess it just depended on what I was driving in at the time I engaged 4WD. This past Winter I've had no trouble at all.
 
Sorry, I didn't follow any specific guides, I just did a search for the disconnect and found a couple threads where people discussed their procedures. The hardest part usually is getting it to come loose from the oil pan.
 
Gearheadvr4 said:
It's small rubber bulb instead of a schrader valve.
Click to expand...

It looks like someone has swapped that service port before. Almost looks like wrench marks on the hex part of the fitting. I wish I had an EXT here to verify that it isn't OEM.:undecided:
 
That's weird, my 04 ext is completely different. Is that even a picture of aTB? Because the dipstick in the picture about to port isn't the same dipstick that's in the picture of your engine bay. But the only port on mine is the valve stem type like for a tire.
 
That is definitely not a TB, looks more like an S10. There should not be any visible rubber in there. It's a valve. The only thing I can think of is that the rubber is dislodged and on top of the valve. There are two. Low pressure port is on the receiver/dryer (can) and the high pressure port is located near the radiator fill cap. The high pressure valve can be damaged if the gauge is disconnected while it's running and under high pressure (ask me how I know :redface:).
 
Yes that picture is representative of the one on mine. I'll try to get a better shot tomorrow morning.

Any ideas on the check engine codes?
 
The P0014 might go away with a cleaning of the camshaft position sensor. There's a write up on it in the how to section. It's really easy.
 
Great write-up. Thanks for the link. For the other code I will check the wire harnesses and replace the air temp sensor. Seems like a good start. After that on to the 4x4 diagnosis.
 
P0014, I would check the actuator plug for oil first,

if there's oil, might as well order a new one...
 
I wouldn't call your ac port messed up or anything but I would conceive that it's been replaced if it's the rubber ball type. Maybe it's leaking because it wasn't made for our system. However, such ports do exist, both Ports on my Mustang are that type.

Edit: I had the p0014 code recently but an oil change cleared it up.
 
Mounce said:
.
Edit: I had the p0014 code recently but an oil change cleared it up.
Click to expand...

a good question to ask the OP since he already changed the oil, is if he used the recommended 5w-30 oil...
 
KNBlazer said:
a good question to ask the OP since he already changed the oil, is if he used the recommended 5w-30 oil...
Click to expand...

Sure hope he did as the visibly "clean" oil cap clearly says 5w-30 in his pic. Anyone who misses that deserves to have problems. :crazy:







:rotfl:
 
Gearheadvr4 said:
Yup, used Mobil 1 syth 5w30
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Although I replaced my Cpas a couple of months ago, I did not have an SES light... what I did have, was oil in the connector, over time the oil messes up the harness... Since 25K miles, I have always used Mobil 1 Synth, EP, and now High Mileage... there were a few specs of crap on the middle screen, normal I guess... bought mine off of ebay, GM originial for $48 shipped...
 
Great post, newbie here too. Suggestion to moderators, a sticky post at the top with things to look for/change/PM would be great. :thumbsup:
 
Great tip. Cheap insurance. This will primarily be a daily driver to work and occasionally on the beach. Towing from the down beach is crazy expensive. I would be pretty mad to be left stranded by a cheap plastic part.

A quick guide on what to look for after buying these or basic info on the oddities of this engine would be great. Like the cpas.... Never would of thought of that. Even though I have an SS, I feel a bit like learning what a trailblazer is all over again because of the i6 & 4x4.


Gevans17 said:
suggest you get underneath it ASAP and check the shifter cable attachment to the gear select lever. It's held together with a cheap plastic bushing, which will eventual crack/fail and leave you stranded. Suggest you replace it with a custom made metal pin from ATFSpeed.com

92-09 Chevrolet Trailblazer Shifter Cable Repair Pin [SRK-112] - $21.95 : ATFSPEED - Automatic Transmission Factory, 954-916-1155
Click to expand...
 
Gevans17 said:
suggest you get underneath it ASAP and check the shifter cable attachment to the gear select lever. It's held together with a cheap plastic bushing, which will eventual crack/fail and leave you stranded. Suggest you replace it with a custom made metal pin from ATFSpeed.com

92-09 Chevrolet Trailblazer Shifter Cable Repair Pin [SRK-112] - $21.95 : ATFSPEED - Automatic Transmission Factory, 954-916-1155
Click to expand...

Or just get a new cable. Can't beat that for $38.

Amazon.com: ACDelco 15785087 Automatic Transmission Cable: Automotive
 
When mine failed, I used a heavy duty elastic band to hold it together until my replacement bushing arrived. I carry a handful of the elastic bands in the glove box now. :yes:

Doug
 
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