Question about 4WD when in 2WD

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Emoto

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So, when we shift our transfer cases into the 2WD position, how much of the forward 4WD stuff keeps spinning and how much stops turning?

Anyone know?

Thanks!

Bob
 

ptsb5a

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Everything under the front still spins. All you've done by sticking the t-case in 2wd is removed the application of torque to the front drivetrain.
 

Atrus

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EVERYTHING still spins.

The only difference is that the front drivetrain spinning from the road isn't connected to the rear drivetrain spinning from the engine/trans.

This is an oversimplification, but think of it as the drive chain in the transfer case is removed. Everything is still spinning, the front and rear gears just aren't connected anymore.
 

sharpy

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Everything under the front still spins. All you've done by sticking the t-case in 2wd is removed the application of torque to the front drivetrain.

thank you!! now then.....the rear axle is doing all the work while in 2wd....correct???cryinghard.gifcryinghard.gif :D
 

Robsama

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I have a question similar so I'm just gonna go ahead and hijack this thread. When driving in slippery conditions, it is bad to shift in and out of 4WD? When I drive home from work some roads are really bad but some are pretty well plowed and fairly flat and straight. I like to shift into 2WD as often as possible to save gas and for less wear and tear overall. Is that bad?

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Emoto

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I have a question similar so I'm just gonna go ahead and hijack this thread. When driving in slippery conditions, it is bad to shift in and out of 4WD? When I drive home from work some roads are really bad but some are pretty well plowed and fairly flat and straight. I like to shift into 2WD as often as possible to save gas and for less wear and tear overall. Is that bad?

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No. Not bad.
 

Atrus

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Not bad, and with a command trac transfer case, I'd consider it necessary.

Unless you have Selec-Trac, you don't want to be in 4WD in any conditions that don't permit wheel slippage, otherwise you'll get driveline binding.
 

rockymountain

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I have a question similar so I'm just gonna go ahead and hijack this thread. When driving in slippery conditions, it is bad to shift in and out of 4WD? When I drive home from work some roads are really bad but some are pretty well plowed and fairly flat and straight. I like to shift into 2WD as often as possible to save gas and for less wear and tear overall. Is that bad?

threadjacked.gif

the exact opposite is bad.
 

HoosierJeeper

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Robsama, do you have an auto ******? Don't you have 4full time then?

And shifting in and out of 4part time doesn't hurt any, it was designed to be able to do that..'shift on the fly'..:D

Some Auto's are Command Trac....most are I think...
 

Marlon_JB2

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Robsama, do you have an auto ******? Don't you have 4full time then?

And shifting in and out of 4part time doesn't hurt any, it was designed to be able to do that..'shift on the fly'..:D

That only applies for export models.

But anywho, that's why Jeep made it "Shift On The Fly". You should have no issues shifting in and out constantly.

And yeah most automatics are Command-Trac. Take any year KJ Sport for example, you're more likely to find a CRD (which includes Selec-Trac over here) than a 3.7L Auto with Selec-Trac. Limiteds are an entirely different story and most of those are Command-Trac too!
 

Robsama

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Robsama, do you have an auto ******? Don't you have 4full time then?

And shifting in and out of 4part time doesn't hurt any, it was designed to be able to do that..'shift on the fly'..:D

'05 Renny with auto trans. Nope, no full time. Just 2HI, 4PART and 4LOW. And N obviously.
 

Dave

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Yeah, mine is a 05 Ltd with selec-trac.

Dave
 

HoosierJeeper

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I've seen non CRD Sports with Selec Trac...

05 Limited with Selec Trac here.
 

LibertyFever

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Not bad, and with a command trac transfer case, I'd consider it necessary.

Unless you have Selec-Trac, you don't want to be in 4WD in any conditions that don't permit wheel slippage, otherwise you'll get driveline binding.

I always get confused when you call it by the tradename. I like to think of them by their purpose.

Part-time = NV-231 = the Command Trac
Full-time = NV-242 = Selec-Trac

Wikipedia Jeep four wheel drive systems page

It still surprises me that the transfercase used in the majority of Jeeps is the NV-231/NP-231. The design hasn't changed much over the years but there are variations.
 

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