2002 Silverado 4X4 Broken? Service 4WD Light

pelletman · #1 03-17-2007, 02:53 PM

Hi Guys,

I have an 02 Silverado Ext cab 4 x 4 with 120K or so. I was plowing today and stupidly got stuck, I had to beat on it a little bit getting it unstuck, and when I was done the Service 4WD light came on, and I seem to have no 4 wheel drive, like the power is not making it to the front wheels. I shut the truck off, the light reset itself, came back on a few minutes later. I tried to read the codes but came up with nothing, I have a fairly decent code reader. Whether it is in auto, 4 Hi or Low, nothing happens. 4 low does make it crawl. Anybody have any insight into this one? Did I break something horrible? It is not making any noises, just not working. I appreciate your input! Thanks Dave

grego10r · #2 03-17-2007, 02:59 PM

all i can say this 4x4 system on this truck its suck my got broke like 4 times and now the transfer case is gone. pure junk are this trucks

MT-2500 · #3 03-17-2007, 04:37 PM

To get codes you will need a engine/transmission capable scanner.
Is the front drive shaft turning or front axle locking in?
Can you hear the transfer case shift from low to high?

pelletman · #4 03-17-2007, 06:02 PM

Thanks for the reply! I have an Innova scanner www.partsamerica.com/codereaders.aspx I think model 3100 but I could be wrong on the model. I think it is a fairly good scanner. Does the presence of the Service 4WD light mean there definitely is a code? I am not getting one with the scanner, even when the light is on. I do not hear the transfer case shift, I am not sure if the front driveshaft is turning, I was alone and couldn't see it when I was driving! I appreciate your help. I'm thinking maybe the actuator is bad and not pulling in? Just a wild guess here. The lights are on on the buttons, it's just that it says it is in 4WD when it is only in 2WD, or at least only the rear wheels are working...

pelletman · #5 03-19-2007, 07:52 AM

The Service 4WD light is now on all the time, and the lights on the switches are off. Any ideas anyone? Thanks! Dave

MT-2500 · #6 03-19-2007, 08:37 AM

Quote:

Originally Posted by pelletman

The Service 4WD light is now on all the time, and the lights on the switches are off. Any ideas anyone? Thanks! Dave

Check your basics first.
All power and grounds and all fuses to 4W shifting.
Will your scanner that is capable of reading transmission and transfer case and body computer data?
If not you will need to find one that does.
If the light is on there is a need or code someplace.

pelletman · #7 03-19-2007, 10:13 AM

OK, I went to a local transmission shop who has a Snap On scanner, and he came up with this code:

CO374 General System Malfunction

Which I guess tells us not too much? He did clear the code, and we did hear either the motor or actuator click when he cleared it. I put the truck in 4WD and drove it around the parking lot, I didn't feel the front wheels fighting me when I turned, so I still think the front wheels are not locked in, and I am leaning towards actuator. I have the GM test procedures which I will probably go through unless someone tells me something definite from this code and my symptoms. The service 4WD light is no longer on, I have only driven it about 4 miles maybe since it was cleared. I appreciate the help, please let me know if you have nay input on this.

Thanks! Dave

MT-2500 · #8 03-19-2007, 11:22 AM

When a code is set the transfer case shifting shuts down.
Plowing is auto mode could have set the code.
After code was cleared recheck all shifting operation.
And yes check front axle actuator for locking front axle.
You may only feel a 4W bind up or crow hop in 4W high or 4W low mode.
Auto mode you may not feel it.

I wold also service the transfer case with the new GM auto trac blue fluid.
In some cases with bad fluid or servere service the fluid will need flushed and re changed.

pelletman · #9 03-19-2007, 01:02 PM

Thanks! I appreciate the input. I'll check that stuff. Are you saying I should not plow in Auto?

OGG · #10 03-19-2007, 04:24 PM

Plowing in 4wd auto will probably cook the clutches in the transfer case. IIRC it's a friction clutch pack and it definitely will wear if your spinning the rear wheels all the time. You are much better off using 4W high than 4wauto

pelletman · #11 03-19-2007, 05:53 PM

Thanks 4 x 4 High it is from now on while plowing.

RPerformance · #12 03-20-2007, 11:47 AM

keep us posted I have a similiar problem.

MT-2500 · #13 03-20-2007, 12:29 PM

Quote:

Originally Posted by pelletman

Thanks! I appreciate the input. I'll check that stuff. Are you saying I should not plow in Auto?

As said plowing in auto matic mode can damage clutches and id what probably set the code.
Always us straight 4W mode for off road 4 wheel stuff.
Auto modes uses clutches to apply torque to front and rear wheels as needed.
Made for highway use when there is wet/slippery conditions.
Does your owners manual cover that part for you?
MT

SDWYZ · #14 01-27-2008, 01:13 AM

I am a fresh newbie and have been researching this stuff all day. I have the same condition as "peelletman" and can use some assistance.

"Pelletman", what was the outcome of your problem?

Anyone else have any ideas.?

Thanks in advance.

MT-2500 · #15 01-27-2008, 09:00 AM

Quote:

Originally Posted by SDWYZ

I am a fresh newbie and have been researching this stuff all day. I have the same condition as "peelletman" and can use some assistance.

"Pelletman", what was the outcome of your problem?

Anyone else have any ideas.?

Thanks in advance.

This post is very old.
Always check the date on a post before replying and if it is old let sleeping dogs sleep.

And with a new problem or your problem DO NOT HYJACK ANOTHER POST always start a new thread on
it and someone will help on it.

MT

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