2002 Silverado 4 X 4 not working

[pelletman]

Hello Everyone,

I had posted a few weeks back on my 4WD not working after getting the truck stuck in a snowbank while plowing. I had the code read, and it was just a general 4WD fault, nothing specific. I jacked up the truck today with all 4 wheels off the ground. When I put it in 4WD, the transfer case engages and starts spinning the front wheels, but I can block one and stop the other. I'm thinking maybe the motor isn't engaging the front axle fully (or at all), and I'm about to check that. Can anyone give me any guidance here?

I have now determined that if I stop the front wheels while it is in 4 high, the front driveshaft stops spinning. Transfer case problem?

Thanks in Advance

Dave

[MT-2500]

Originally Posted by pelletman

Hello Everyone,

I had posted a few weeks back on my 4WD not working after getting the truck stuck in a snowbank while plowing. I had the code read, and it was just a general 4WD fault, nothing specific. I jacked up the truck today with all 4 wheels off the ground. When I put it in 4WD, the transfer case engages and starts spinning the front wheels, but I can block one and stop the other. I'm thinking maybe the motor isn't engaging the front axle fully (or at all), and I'm about to check that. Can anyone give me any guidance here?

Thanks in Advance

Dave

Give us the info you posted from other from other post or go back to it.
What engine and transfer case?
Any check lights on or blinking?
What is it doing or not doing?


OBD11 scanner will not get the job done on transfer case testing or checking.
You need to get it on a good engine /transmission/transfer case capable scanner and read out the transfer case codes.
Post back code and we can help.
A good scanner will have codes set if something is bad and all so some test for transfer case.

On front axle turn drive shaft and block one wheel. If locked in the other wheel will spin as you turn drive shaft.

[pelletman]

I had it scanned at a transmission shop with a snap on scanner. Is that good enough? It is a 246 transfer case made by New Venture Gear. 5.3 litre 2002 V8. The lights are on to indicate whether it is in 4 wd or not, but they seem to be working correctly. Originally I had a 4WD Service light coming up, but we turned it off with the scanner. The code was a general 4WD fault, it was very vauge. There are no codes now, or at least no lights on.

On front axle turn drive shaft and block one wheel. If locked in the other wheel will spin as you turn drive shaft.

I don't understand what you are saying here. If I block the wheel are you saying that I shouldn't be able to turn the other? Please be more specific.

I have it jacked up and on 4 jackstands. When I put it in 4WD the front driveshaft turns and the wheels turn, but I can stop both the front wheels from turning when it is in gear and running.

Thanks!

Dave

[MT-2500]

The scanner is only as good as the operater and cartiages it has.
Was it scanned with the transfer case mode or just a obd11 scan?
What was the code no?
If the light was on there should have been a code no past history or present?
When checking for front axel lock up always use 4W high or 4W low mode.
Not auto mode. In auto the front axel will lock up but front end drive shaft will not be locked with rear shaft.
Lock in 4W high or 4W low and put transmision in park and raise up right front side tire.
If you can spin it it is not locked in.
Another fast check is put it in 4H or 4L and make a sharp turn on dry payment.
If you have crow hop it is locked in.
MT

[pelletman]

The other post is here:

http://www.automotiveforums.com/vbul...ight=pelletman

This was the code:
CO374 General System Malfunction

I do not seem to have any wheel hop when I turn in 4WD. Any more ideas? I appreciate the help!

Thanks!


Dave

[MT-2500]

Is the front axle locking in?
Will the transfer case shift to and out of low range?
Has any codes come back?

[klinn]

Here is what the GM service manual sais about the code you have. I wonder if this code was created when you stopped the wheels when you had it jacked up. Just a thought.

DTC C0374

Circuit Description

The transfer case shift control module senses rear to front wheel slip, a difference of rear to front wheel speed and attempts to correct the difference by activating the encoder motor, to apply more torque to the front wheels.
Conditions for Setting the DTC

The transfer case shift control module is unable to correct sensed slip for 10 consecutive seconds.
Action Taken When DTC Sets

All transfer case shifting will be disabled while the DTC is present and current.




The diagnosis of this will need a scan tool, probably a GM scan tool. There are some special functions that need to be performed, and I don't know of the snap-on scan tool is cabable. I could post the instructions if you have a scanner that would do that. Hope this helps.

[pelletman]

The other post is here:

http://www.automotiveforums.com/vbul...ight=pelletman

This was the code:
CO374 General System Malfunction

I do not seem to have any wheel hop when I turn in 4WD. Any more ideas? I appreciate the help!

Thanks!


Dave