4WD Auto questions

[Mr.Smith]

My new 24 Rubicon X has 4wd Auto. Is this pretty much the same as AWD? Are you all leaving in 4WD auto for the winter or 2wd.?

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[At Risk Ute]

4H auto involves clutch packs. I use it on pavement when it’s slippery. 2H if it’s dry.

 

[58Willys]

Yes, pretty much AWD.

 

[Mr.Smith]

Does it do any damage to leave in 4 auto all the time. I ask because wife drives and I doubt she will remember to go back and forth

 

[Bob Burd]

No damage

 

[dragoneggs]

No damage

No damage but additional unnecessary wear. Sounds like a little training would be prudent.

 

[Mr.Smith]

No damage but additional unnecessary wear. Sounds like a little training would be prudent.

She would love that.

 

[TrentYoung]

My new 24 Rubicon X has 4wd Auto. Is this pretty much the same as AWD? Are you all leaving in 4WD auto for the winter or 2wd.?

Just always leave it in 4H Auto.

 

[Ratbert]

What's your owner's manual say?

 

[At Risk Ute]

No damage

392 guy who begs to differ. Use 4H Auto when you need it. Teach her how to throw the transfer case stick fore and aft.

 

[GATORB8]

What's your owner's manual say?

Surprisingly silent:

Most of the difference will be FAD engagement (if your 24 even has it), it's engaged in 4Auto, so more moving mass and a tad less fuel mileage is possible.

Looks like you'll definitely want it in 4 Auto tonight.

 

[Ratbert]

Surprisingly silent:

Most of the difference will be FAD engagement (if your 24 even has it), it's engaged in 4Auto, so more moving mass and a tad less fuel mileage is possible.

Looks like you'll definitely want it in 4 Auto tonight.

Yeah, it implies that he/she should be using 2HI on dry hard roads, but doesn't explicitly say it.

 

[TheRaven]

Auto 4WD is not the same as AWD. AWD is an "always-on" system...it vectors power and clutches are allowed to slip but there is always a mechanical connection with AWD. Auto 4WD can completely disconnect the front axle. It will only re-connect when rear wheel slip is detected and when it does, it's not a slip, it's full-on...requiring the front diff to vector torque between the front wheels.

EDIT: I came back to re-read this and I realize that the way I worded the above is not clear. I do not intend to say that the Auto 4WD cannot slip AT ALL. Just that it completely disengages the front axle as opposed to increasing slip to the point where only a very small amount of torque is transmitted.

Because of the way Auto 4WD disconnects and reconnects the front axle, it's not advisable to leave it on all the time...that would subject the front axles and diff to additional unnecessary stress. Will it actually make a difference over, say, 100k miles? Dunno. But it could...so it makes sense to leave it in 2H on completely dry roads and only use Auto when the roads are at least a little wet.

 

[GATORB8]

Auto 4WD is not the same as AWD. AWD is an "always-on" system...it vectors power and clutches are allowed to slip but there is always a mechanical connection with AWD. Auto 4WD can completely disconnect the front axle. It will only re-connect when rear wheel slip is detected and when it does, it's not a slip, it's full-on...requiring the front diff to vector torque between the front wheels.

Because of the way Auto 4WD disconnects and reconnects the front axle, it's not advisable to leave it on all the time...that would subject the front axles and diff to additional unnecessary stress. Will it actually make a difference over, say, 100k miles? Dunno. But it could...so it makes sense to leave it in 2H on completely dry roads and only use Auto when the roads are at least a little wet.

The “full time” TCase is able to vary clutch engagement in 4 auto
From what I’ve read.

 

[Mr.Smith]

What's your owner's manual say?

"Refer to random people on forum"

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