2003 Tahoe Service 4WD?

[bmkearsley]

Just bought a 2003 Z71 tahoe w 96,000 miles on it. Went to switch it to 4WD for the first time I was going off road, and the red light came on and the dash board said service 4WD...any ideas or what the prob may be or cost of getting it serviced or where i can get it serviced...I live in charlotte if there are any users in the area

 

[Michael Dutch]

Had "service 4wheel drive" warning coming on as well. Had my buddy scan it (autozone also can do it for free). No codes came up. So withthe key on,we switched it through all the drive ranges, 2hi,4hi and 4lo,just to be sure actuator was working (you can hear it),then did some light off roading,through all the ranges. Everything works fine....I ignore the warning when it comes up. Mine only comes up occasionally.

 

[s--k]

If the problem is like my 2005 Yukon, the problem will get more frequent and more severe.

It starts with an occasion service 4WD or traction control. Then when in normal 2 High range the indicator lights on the 4WD shift button panel will not be lit up properly, then the buttons will not respond. This all happened to me. Next I read that the transfer case will shift on it's own, sometimes into 4 low and may or may not be shifted back to 2WD. I read that somebody had to have their's towed after it went to 4 low and they couldn't get it back.

On some of the older models that button panel goes bad, but not on the mid-00's. I changed my transfer case actuator motor. It mounts directly on the transfer case. I can't remember what happens exactly, but something inside there starts to short out or gets corroded and malfunction.

It is an easy change, just remove the front driveshaft and you have access to it. The part is expensive. Major auto parts stores sell reman units. I got an AC Delco piece that was new (Mexico) and problems went away.

 

[scrnchr]

I'm fighting this same problem.

How do I know if it's the 4WD selector switch or the transfer case motor encoder ring?


Here are my details:

I have a 2004 Tahoe LS.

Two years ago, the 4WD switch buttons started acting up. It would light up red, like in neutral, then sometimes not go into 4-Hi, or maybe stay in 4-Hi and not go into 2-Hi right away. From what I recall, I disconnected the battery or something and the system reset and worked fine ever since.

Until this month. First, it wouldn't go into 4-Hi. It would only stay in 2-Hi. The red neutral light came on one time, but mostly it would just stay in 2wd, and when I'd push 4-Hi that light would flash for a while but it would never go into 4-Hi. It also wouldn't go into Auto (that light would flash, too, when I pushed Auto, and sometimes it would stay on Auto for a few minutes, but it wouldn't really go into Auto).

btw, when I start the truck, all of the 4WD switch lights come on, so I know they are good.

I drove the truck in some pretty good snow last week. While going through a snow drift, I pushed the 4-Hi button. It shifted into 4-Hi. And now it will not come out of 4-Hi!! It is stuck in 4WD.


I have read lots of forums about this. Here is what I have tried:

1. I pulled the TREC fuse for about a minute. The fuse itself is good. This didn't help at all. I've done this on two different occasions now. I also pulled and checked a bunch of other fuses.

2. I disconnected the battery for 45 minutes. It didn't help at all.

3. I pulled the dash trim and removed the 4WD selector switch. I took it apart to check for bad solder joints I could fix (per many forum posts I've read). I am unable to remove the circuit board from the plastic back of the switch (the pins go through the plastic and won't pull out). I'm assuming the soldering mentioned was on that backside, because there's not much to see on the front side. I reassembled the whole thing and put it back in. It still acts exactly the same. It is in 4-Hi. If I push 2-Hi or Auto or 4-Lo, they flash but it won't go in. Well, occasionally, it has always lit up the Auto light like it went into Auto, but it didn't really, and eventually the light goes back to 4-Hi. I have tried shifting while in Drive, while in Neutral and rolling, while and after backing up, also with the engine off, in neutral, brakes on--everything I've read to try. Nothing helps.

4. I am thinking about replacing the transfer case motor encoder ring. There is a good video of doing that here:
http://www.youtube.com/watch?v=pXa61y5pqz8&feature=youtube_gdata_player
Does anyone know if you really have to reflash the program? Another GM PIA.


So.....................

How do I know if it's the 4WD selector switch or the encoder ring?

I can't find the 4WD selector switch on NAPA or AutoZone websites. Anyone have the part number? The switch is on eBay (with multiple part numbers), but I'd like to buy it, try it, and if it doesn't help, return it immediately and buy the encoder ring (I guess).


I know some posts refer to a TSB and to reading the powertrain codes, but from what I've read the C0327 code basically just say "it's not working" and doesn't really tell you what to fix. Also that many posters say when they take it to a dealer, they are usually told it's throwing too many codes to help anything. Great.


If you have any thoughts, experience, advice on this, I would greatly appreciate it. We need this truck for my wife to drive to work, and I don't want it driven on dry pavement very long like this, or it will probably tear up the drivetrain.

Thank you.

 

[s--k]

I believe the solder problem on the dash switch applies only to older models. I can't remember the years, but I do recall reading that GM upgraded the switch after that issue. Don't recall the year, but I know my 05 had the newer switch design. I am guessing if your switch didn't look like the descriptions you read on the solder connection corrections then you have the newer switch.

I got an AC Delco transfer case actuator motor from Summit Racing. Not sure if I still have the invoice or part number. I know for sure that Napa has it because I price checked their rebuilt units before buying my new unit. Napa may just call it something else. The whole assembly is referred to as the an actuator motor.

There are different part numbers. The differences that I am aware of is the number of wires on the plug. If you change actuators make sure you verify the number of wires. I think it is 4 vs 5 if I remember right. I had to return the first actuator to Summit because I had the wrong number and therefore the wrong plug. I got the part number off the internet research. Once I knew what the wrong number was, there was only one other number that was listed for my year so that had to be it and it was.

I do think that you can disassemble your existing actuator and just replace the electronic component, but I did not choose to go that route.

Once you remove the driveshaft access is easy as is removal and installation of the actuator itself. I believe I swapped mine out with the battery disconnected, but I did not do any sort of reflash to the computer and everything has worked perfect since. I did that a little over a year ago.

I don't know specifically how to tell you if it is the dash switch or the actuator assembly on the transfer case. All I know for me, is I bought an $80 switch first, but after I swapped it out that didn't cure the problem so I moved onto the next most likely cause.

 

[scrnchr]

I think you're probably right, so I picked up a used transfer case motor. I didn't feel like messing with the encoder ring. But now I can't get the old one out. The guy in the video fails to mention that the front driveshaft has to be turned just right to have clearance to pull the one bolt. My truck is stuck in 4WD, so the front DS doesn't turn by hand. And of course every time I run it up the ramps the DS isn't quite in the right spot. I'm trying to drop the front DS and can't get it. I have the clamps pulled on the front u-joint. I cannot get the driveshaft to slide back into the transfer case. I've tried prying gently and tapping a hammer on a block of wood against the DS... nothing. I'm starting to think the front end needs to be on jackstands rather than with the wheels on ramps, so that the front differential can drop down to take the compression off the front driveshaft--is that right? This is driving me crazy. I am very frustrated with the two GM trucks I own.

 

[s--k]

As my memory goes, I had the truck supported on jack stands on the frame with the front suspension drooped. I think I only disconnected the driveshaft from the t-case yoke, then I just let it dangle out of the way still connnected to the front diff. I didn't consider trying to do the job with the driveshaft in place, just looked too tight.

Those ujoint caps like to get stuck in the saddles of the yoke. Probably just a large pry bar device between the yoke and ujoint and some persuasion will do the trick.

If you haven't done it already I would verify that wire count on your plug so you make sure you have the right one. Nothing worse than tearing it down thinking you are home free only to learn you have the wrong part...like I did.

 

[scrnchr]

OK, got it fixed. I appreciate all your advice, s--k. I gave up on the driveshaft. Moved the truck back and forth a little on the ramps until things were lined up enough to get that one bolt out. The old encoder motor looked like it was mounted crooked. Two of the bolt ears on the casting had broken off. Dirt was packed between the motor housing and the transfer case housing. The spline wasn't engaging enough to shift. I'm really glad I didn't buy just the encoder ring because the old motor housing was trashed. It's not that easy getting the new one all lined up, engaged and getting the bolts started with the little room there is to work. For others that might be doing this, remember to turn the splined shaft on the transfer case to match the angle of the splines on the new motor. Don't try to turn the motor angle, because it has the encoder ring in it. Now it shifts in and out of 4WD perfectly. So recently I've gone through replacing the vent solenoid and MAF sensor to get it to pass emissions, plus the 4WD problem; now I wait for the next thing to go wrong, lol. My Jimmy always has problems, too. Replaced its fuel pump last winter, what a pain in the butt. I love GM trucks when they're running, but whenever I work on them I swear, no more for me.

 

[Luthandrian]

I found the fix for this. I had the same issues and tossed around options like a lot of others have that I've read about.

First let me describe my issue:

The service 4WD light would come up on the dash
The push buttons would work intermittently
We couldn't shift from 2hi to 4hi etc.
Sometimes the car would display that it was in neutral but we still had power to the wheels.

Taking out fuses and continually resetting it would temporarily fix the issue.

Removing the push button switch and cleaning the solder points temporarily fixed it.

Then I replaced the push button. It fixed it for awhile, then the problem returned.

Then I replaced the 4WD actuator, same result, temporary fix.

Finally I have replaced the transfer case motor itself. This did it!

Within this motor is the "transfer case range position sensor" this sensor tells your dash which position your transfer case is in so that it can display it. I believe that having the car in AUTO 4WD wears out this sensor. Once it goes and starts glitching out, your car will not know which position its in and will not work properly. Other systems that rely on the information from this sensor will start acting out as well.

Instead of purchasing only the sensor and worrying about dismantling my transfer case motor, I just bought a whole new motor off Rockauto for $165.

Replacing these parts were very easy

The push button on the dash is simple
The actuator literally just screws out with one connector
The motor itself required removal of the drive shaft (4 easy bolts) then the 3 bolts to hold the motor on the transfer case. You will have to turn your transfer case gear to the neutral position manually (gently) to align with the new motor, then once its all plugged in remember your transfer case is in neutral and you will have to switch it into 2HI or something to drive.

My suggestion is do not use AUTO FWD, this car is a shift-on-the-fly so you can switch it into 4WD without stopping (just don't be turning when you do so). Don't let your car switch in and out of 4WD on its own in my opinion.

 

[Vista Cruiser 69]

Guys,
understand this is quite an old thread but interesting for me facing my first Tahoe 4WD wintertime...When I bought it last March (2001 LT Canada/EU Export version) I checked all drive functions and all worked well. I still engage 4WD Hi and Lo occasionally to keep it in motion somehow. What i could not check yet was this Auto 4WD thing. I engaged it once on grass at home to find out but apart from a ruined lawn and a debate with my wife I think it stayed on 2WD. I'm not planning to permanently use this Auto 4WD position, but can someone tell me what it actually does? How does it engage, what triggers it, ABS sensors? How quick it should lock up? and - if it had nothing to do but waiting for slip, is there a difference in driving at Auto 4WD and 2Hi? The German owners manual is a bit autistic on it, repair manual didn't tell details as well. Any insights welcome!
Keep the Glass to the Sky!