How to Operate the 4WD?

[wamba the fool]

Greetings,

I am a complete newbie when it comes to 4WD controls. I bought a 2005 GMC Yukon XL over the weekend and I want to make sure I understand how to operate it properly.

I have a few questions:

1. Do I need to stop the vehicle to engage the 4WD Auto setting? Is it the same for the other settings?
2. Can I drive at highway speeds with the 4WD Auto setting on?
3. Any other insights or tips would be greatly appreciated.

Thank you in advance for your help!

 

[strutaeng]

Greetings,

I am a complete newbie when it comes to 4WD controls. I bought a 2005 GMC Yukon XL over the weekend and I want to make sure I understand how to operate it properly.

I have a few questions:

1. Do I need to stop the vehicle to engage the 4WD Auto setting? Is it the same for the other settings?
2. Can I drive at highway speeds with the 4WD Auto setting on?
3. Any other insights or tips would be greatly appreciated.

Thank you in advance for your help!

Please read the owners manual. It talks in detail on how to operate the transfer case.

If you don't happen to have the hardcopy, you can find it online.

 

[Doubeleive]

Greetings,

I am a complete newbie when it comes to 4WD controls. I bought a 2005 GMC Yukon XL over the weekend and I want to make sure I understand how to operate it properly.

I have a few questions:

1. Do I need to stop the vehicle to engage the 4WD Auto setting? Is it the same for the other settings?
2. Can I drive at highway speeds with the 4WD Auto setting on?
3. Any other insights or tips would be greatly appreciated.

Thank you in advance for your help!

the only thing you really NEED to worry about for the most part is not to put it in 4lo if so equipped. unless you are stopped and not while traveling at speeds over 35 (i think, could be 30mph) in any case it will tell you in the owners manual. otherwise you can switch from 2wd/4wd/auto while moving or stopped.
you will get mixed opinions on using "auto" I use auto 24/7 and have since it was a thing and have never have had any problems. some state it puts wear on the front diff which is true in a sense but at the same time it can reduce stress on the rear diff which is a weak point.

 

[the 18th letter]

the only thing you really NEED to worry about for the most part is not to put it in 4lo if so equipped. unless you are stopped and not while traveling at speeds over 35 (i think, could be 30mph) in any case it will tell you in the owners manual. otherwise you can switch from 2wd/4wd/auto while moving or stopped.
you will get mixed opinions on using "auto" I use auto 24/7 and have since it was a thing and have never have had any problems. some state it puts wear on the front diff which is true in a sense but at the same time it can reduce stress on the rear diff which is a weak point.

Is it a preference or is there a functional reason you keep it 4 auto?

 

[Scottydoggs]

2 hi to 4 hi, or 4 hi to 2 hi you can just hit the button while driving, 4 low you must come to a full stop put the truck in N, then hit the 4 low button. full stop again back to N to take it out of 4 low.

as far as speed in 4 hi, ive driven up to 75 mph in my work trucks with a snow plow on the front. manual says to not exceed 45-50 iirc.

owners manuals are free on line to dl and read.

 

[steiny93]

The gmc auto 4wd system isn't intended for 24/7 usage (it absolutely will cause powertrain wear); the advice above about auto 4wd reducing rear diff load is incorrect.

Here is why (generalizing)
- auto 4wd uses a clutch within the transfer case; when rear slippage occurs torque is added to the front via this clutch
- 4 hi means both front and rear axles get torque all the time, albeit at different speeds (why this is bad with high traction)

The wear during auto 4wd is because all the components are lit and getting some torque when engaged.

The reducing rear diff load comment in auto 4wd is incorrect because the rear diff gets 100% of the load until it slips before the front sheds torque. If one was in 4 hi the reduction of rear diff load would be a true statement.

 

[Joseph Garcia]

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.

 

[Marky Dissod]

... bought a 2005 GMC Yukon XL ... want to make sure I understand how to operate it properly.
1a. Do I need to stop the vehicle to engage the 4WD Auto setting?
1b. Is it the same for the other settings?
2. Can I drive at highway speeds with the 4WD Auto setting on?
3. Any other insights or tips would be greatly appreciated.

1a. No. But also, see 1b.
1b. Scottydoggs got it right:
To switch to 4Lo, STOP, put the truck in N, then put the truck in 4Lo, and then off you go.
To switch out of 4Lo, STOP, put the truck in N, then put it in 4Hi or 2 Hi, then off you go.

2. Yes, but I can't recommend it unless available traction is 'wet' or 'loose' or 'slippery' or 'iffy'.
It's not the AWD system in a Subaru WRX or Mitsu Lancer Evo.

3. To preserve the transfer case as long as reasonably possible, a few rules of thumb:
I won't consider pressing 'Auto 4WD' unless it's raining pretty hard.
I won't consider pressing '4WD High' unless it's snowing.
I won't consider pressing '4WD Low' unless '4WD High' isn't enough to get me unstuck.

Off-roaders with more experience than a NuYawrka will of course have better advice.
Another post shortly ...

 

[Fless]

For the mode switch in and out of 4LO, the truck can be rolling up to 3mph (and rolling can help it engage smoother, although there will still be an audible clunk when it happens). Check the owner's manual for your rig.

 

[Marky Dissod]

I ONCE made the mistake (in my experience) of leaving Auto4WD on in the dry.
Coming out of a surprisingly torrential downpour which stopped most NuYawrkas from driving, I was coming back from Five Guys with dinner, driving into a garage.
I've a fetish for backing into parking spaces whenever possible.
Transitioning from the outside's lack of grip to the dry painted grippy garage floor inside, the steering felt noticeably odd in Auto4WD compared to 2Hi, despite driving under 10MpH.
Besides the steering feel change, the turning radius actually got slightly wider.
I won't leave Auto4WD on in the dry again, just in case.