'01 Gmc Transfer Case

GM For Life · 03-25-2007, 08:44 AM

I have a problem with my '01 GMC Sierra 5.3L, auto trans, auto 4x4. Transfer case developed a leak and was low on fluid. I drained the remaining fluid and refilled it with the GM spec auto transfer case fluid. Now it seems that the transfer case is always engaged in 4x4. I know the actuator motor for 4x4 high is working properly because a guy I know with a scan-tool came and checked it. But the front drive shaft is always turning. What is going on in there?

Thanks Guys and Gals.

75K30 · 03-25-2007, 09:06 AM

Exactly what was this special GM spec auto transfer case fluid? Even though you have an electronically controlled t-case, it is still considered a manual case. The autos were fully automatic cases that engaged the front axle when the rear started spinning. These were used on AWD astros, and equal vehicles. But I do believe that you have a NP 246. The book calls for regular old trans fluid, (dex III). There is a GM synthetic that is blue, but you should never see any advantgases to running this. Witohout any clutches to bind, you can get away with about any dex III fluid.
What type of fuid did you use?

GM For Life · 03-25-2007, 10:39 AM

Thanks for the quick reply. I used the blue stuff from the dealer. Don't remember what is was called. But I guess he took me for $7 a quart when I could have used Dex III.
So do you think that even though it tested fine, the actuator is stuck?

75K30 · 03-25-2007, 11:00 AM

It is very possible that there is an actuator problem. You can disconnect the front axle 4wd sensor, and drive the truck for a mile, or two. The sensor will not see that the truck is in 4wd, and default back to 2wd operation. This will get you back on the road until you can fix the problem entirely. You may want to verify the switch. These are known to go bad, and will cause troubles as you have stated. Time to break out the muti-meter, and do some electrical troubleshooting. Some have claimed that the 4wd control module goes bad, and prevents the thing from coming out of 4wd. Others may point to the actuator itself, but it will take some time to narrow it down. Good luck there.
That blue stuff is for the AWD systems, and is designed to prevent the clutches inside from chattering. Probably can't hurt anything if you run it, and yeah, it is a little on the spendy side.

GM For Life · 03-25-2007, 12:10 PM

Hey, thanks. I appreciate the insight.

-GM

72'CaminoKid · 03-25-2007, 01:14 PM

my buddy has the same truck, and while going down the road, his would randomly try to engange 4wd. i think the actuator was his problem. i believe i remember him telling me the guy at the shop told him this has beena frequent problem. so i would think that the fluid change had nothing to do with it

GM For Life · 03-25-2007, 01:52 PM

Thanks Camino, I am open to any suggestions anyone has.

And I forgot to mention that technically, it is not running in 4x4 right now because the front differential isn't locked in. Just the transfer case. So would that eliminate the switch as the problem?

72'CaminoKid · 03-25-2007, 02:41 PM

do u get service 4wd light?

GM For Life · 03-26-2007, 09:28 AM

No service lights of any kind.

Baero · 03-27-2007, 06:10 PM

I am having the exact same issue (02 hd 1500 with auto transfer case), someone told me that with an auto transfer case the front shaft is always turning. Is this true, because I cannot turn the front shaft by hand in 2 wheel drive.

Have you found anything more out GM for Life?

03-25-2007, 08:44 AM	#1
GM For Life Full Member Join Date: Sep 2006 Posts: 24	'01 Gmc Transfer Case I have a problem with my '01 GMC Sierra 5.3L, auto trans, auto 4x4. Transfer case developed a leak and was low on fluid. I drained the remaining fluid and refilled it with the GM spec auto transfer case fluid. Now it seems that the transfer case is always engaged in 4x4. I know the actuator motor for 4x4 high is working properly because a guy I know with a scan-tool came and checked it. But the front drive shaft is always turning. What is going on in there? Thanks Guys and Gals.

03-25-2007, 01:14 PM	#6
72'CaminoKid Senior Member Join Date: Jun 2005 Posts: 2,756	my buddy has the same truck, and while going down the road, his would randomly try to engange 4wd. i think the actuator was his problem. i believe i remember him telling me the guy at the shop told him this has beena frequent problem. so i would think that the fluid change had nothing to do with it __________________ 99 suburban xlt 96 silverado 91 wrangler (my baby ) 08 Honday shadow 750 (my mistress)

03-25-2007, 02:41 PM	#8
72'CaminoKid Senior Member Join Date: Jun 2005 Posts: 2,756	do u get service 4wd light? __________________ 99 suburban xlt 96 silverado 91 wrangler (my baby ) 08 Honday shadow 750 (my mistress)

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03-25-2007, 09:06 AM	#2
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	Exactly what was this special GM spec auto transfer case fluid? Even though you have an electronically controlled t-case, it is still considered a manual case. The autos were fully automatic cases that engaged the front axle when the rear started spinning. These were used on AWD astros, and equal vehicles. But I do believe that you have a NP 246. The book calls for regular old trans fluid, (dex III). There is a GM synthetic that is blue, but you should never see any advantgases to running this. Witohout any clutches to bind, you can get away with about any dex III fluid. What type of fuid did you use?

03-25-2007, 10:39 AM	#3
GM For Life Full Member Join Date: Sep 2006 Posts: 24	Thanks for the quick reply. I used the blue stuff from the dealer. Don't remember what is was called. But I guess he took me for $7 a quart when I could have used Dex III. So do you think that even though it tested fine, the actuator is stuck?

03-25-2007, 11:00 AM	#4
75K30 Senior Member Join Date: Jul 2006 Posts: 2,992	It is very possible that there is an actuator problem. You can disconnect the front axle 4wd sensor, and drive the truck for a mile, or two. The sensor will not see that the truck is in 4wd, and default back to 2wd operation. This will get you back on the road until you can fix the problem entirely. You may want to verify the switch. These are known to go bad, and will cause troubles as you have stated. Time to break out the muti-meter, and do some electrical troubleshooting. Some have claimed that the 4wd control module goes bad, and prevents the thing from coming out of 4wd. Others may point to the actuator itself, but it will take some time to narrow it down. Good luck there. That blue stuff is for the AWD systems, and is designed to prevent the clutches inside from chattering. Probably can't hurt anything if you run it, and yeah, it is a little on the spendy side.

03-25-2007, 12:10 PM	#5
GM For Life Full Member Join Date: Sep 2006 Posts: 24	Hey, thanks. I appreciate the insight. -GM

03-25-2007, 01:52 PM	#7
GM For Life Full Member Join Date: Sep 2006 Posts: 24	Thanks Camino, I am open to any suggestions anyone has. And I forgot to mention that technically, it is not running in 4x4 right now because the front differential isn't locked in. Just the transfer case. So would that eliminate the switch as the problem?

03-26-2007, 09:28 AM	#9
GM For Life Full Member Join Date: Sep 2006 Posts: 24	No service lights of any kind.

03-27-2007, 06:10 PM	#10
Baero Junior Member Join Date: Mar 2007 Posts: 1	I am having the exact same issue (02 hd 1500 with auto transfer case), someone told me that with an auto transfer case the front shaft is always turning. Is this true, because I cannot turn the front shaft by hand in 2 wheel drive. Have you found anything more out GM for Life?