Four Wheel Drive "Failure"

[mojave mark]

Just curious if this has ever happened to anyone on the forum. I have a 2008 Sierra 1500 pickup with 4 wheel drive. The four wheel drive is controlled by a dash mounted control that can be set on auto or 2wd or 4 hi or 4lo. I spend most of my time mavigating the wilds of urban so. cal. The system engaged without asking into 4lo and would not disengage. I took it to the local gmc dealer. After 1.5 days of investigating, they said that it was fixed after they "reprogrammed a module" I asked them what should I do if this happens out in the middle of bumbleep. Their response "This is very rare; we've never seen this before" I'm glad they fixed it without charge, but I'm not feeling too good about it not happening again. Any thoughts from the forum?

 

[chnlisle]

1. You might want to ask them if there's away it can be engaged manually under the truck.
2. Perhaps go to one of the Sierra forums and see if anyone else has had the problem and they know how to engage it manually.
3. Buy a Dodge.

 

[HERR42]

1. You might want to ask them if there's away it can be engaged manually under the truck.
2. Perhaps go to one of the Sierra forums and see if anyone else has had the problem and they know how to engage it manually.
3. Buy a Dodge.


what an awful thing to tell someone who is asking for comments!

why would anyone buy a damn failure-fiat?

a trusty ford is the solution! ...but no running boards.

 

[chnlisle]

what an awful thing to tell someone who is asking for comments!

why would anyone buy a damn failure-fiat?

a trusty ford is the solution! ...but no running boards.

Oh Jeff, I am one with my Fiat Ohmmmmmmmmmmmmmmmmm

 

[DirtyDog]

Don't mind these guys Mark. If they had any useful info at all I'm sure they would share it. I think we just have no idea.

 

[chnlisle]

Don't mind these guys Mark. If they had any useful info at all I'm sure they would share it. I think we just have no idea.

Hey I resent that.... I think it would be a good idea to see if it can be engaged manually. I was able to to it on my old t100. These things are usually vacuum activated

 

[DirtyDog]

Hey I resent that.... I think it would be a good idea to see if it can be engaged manually. I was able to to it on my old t100. These things are usually vacuum activated



I stand corrected. That particular part was a good idea

 

[craig333]

Thats one of the reasons I made sure my truck had the manual stick. There has to be a way to do it manually, whether its practical or not out in the boonies I don't know.

 

[Bat]

If your really screwed just unbolt the front drive shaft but there has to be a simpler way

 

[EdoHart]

On the Chevy/GMC electronically controlled transfer case, the problem is usually located at the selector switch. You may have to replace the switch, but before I would do that, I would remove the switch from the dash and clean the contacts with electronic parts cleaner.

 

[fish more]

On the Chevy/GMC electronically controlled transfer case, the problem is usually located at the selector switch. You may have to replace the switch, but before I would do that, I would remove the switch from the dash and clean the contacts with electronic parts cleaner.

The most problems with GM's shift on the fly is the transfer case shift module located on what GM calls the encoder motor, if the system fails to shift in or out of 4wd, you can remove the encoder sensor, held on with torque screwss and manually shift the transfer case, you just have to remember how the encoder sensor is clocked when you remove it. You will have to move the sensor cam to the proper position before putting back into place. When I worked for a Chevy dealer, we had more problems with the encoder sensors than the switches, but we replaced a few switches also. If still having a problem, "Cash for Clunkers"

 

[4llamas]

Mark,
I have a 2001 Sierra 1500 4WD. When the truck had about 20K miles the push button switched failed, as in it would not stay in 4WD. A new switch fixed it. Easy DYI job, the instrument panel cover snaps off and on. I think it was very good advise to check the Sierra groups. Even better advise, don't buy a Dodge. JUST KIDDING!
Good luck and enjoy.

 

[Stan@FourWheel]

I don't think this would be the problem, but if your stuck again, it would be worth a try.

"TAKE THE TRUCK OUT OF THE 4X4 MODE"

"BACK UP FOR 20 OR 30 FT."

Put the truck in drive and see what happens.

Some of my older trucks actually had notes in the owners manual (I think?) telling the drive to back up a little after dis-engaging the 4x4.

My 1997 Ford F-150 4x4 was manual shift 4x4 on the floor (no push button to engage), but I had to back up a few feet and it would pop out of 4 wheel drive

?

 

[mojave mark]

I appreciate everyone's input. I have another 18 months on the lease so the "buy a dodge" option is a possibility. The truck is working fine now. When it happened, I was able to limp to the dealer in 4lo. My concern about trying to fix this problem in the middle of nowhere is that messing with the electronics can sometimes disable the whole rig. Stan, thanks for the "try backing up option"; that has worked years ago on some other family 4x4's.

 

[RonSchon]

I had an 03 Dodge and an 04 GMC with the electronic selector - was never comfortable with it. My Dad's F150 got stuck in 4-low a couple of different times. PITA. That was one of the things that made me want my current steed - the manual selector. A few less fail points. Driving a Dodge, I understand that minimizing failure points is a must... :zing:

 

[Barko1]

When I got my 99 F250 with manual low range engagement and manual locking hubs I thought that was a step back but the more I read there better off I think I am

 

[winter200]

Haven't had to deal with the new transfer cases yet but it does indeed sound like the encoder motor sensor. They had issues with them in the previous model including the 3/4 ton also. The fix on the older ones was to simply pull the 4 wheel drive fuse and shut the truck off. Pull key, wait and restart. They usually always went to 2 wheel high.