Using Auto 4x4 vs. 4H

[TonyClifton]

Hi guys. I have a 2003 ZL1 and have been doing more offroading lately. I tend to leave use the Auto 4x4 setting on these 10 to 20 mile long trails as I seem to be getting by that way OK. Only a couple times do I put it directly into 4H or 4L for a clear tough spot. Would I be better off leaving it in 4H? Am I forcing it to go in and out of 4x4 by using the Auto feature?

[dsponder]

I think with auto the transfer case is always engaged but when your tire spins it locks in the actuator on the front axle. I would leave it on auto for a light trail.

[bai78]

You should be fine, as this is what the feature was designed for.

[Underpowered]

when i am actually off road, i put it in 4 hi and leave it until i need 4lo. but i snow i usually leave it in auto 4x.

never really even thought about using auto off road, but where i go at, you need 4wd most of the time anyway

[TonyClifton]

I asked because I was with some more frequent/experienced offroad guys and I noticed all of them left their various make/model rigs in 4H. I was surprised at how little I actually needed the 4x4 engaged despite some questionable trail conditions. Leaving in 4H gives me more front end gear whine and noise while turning the steering wheel (not a lot, I don't think I have a problem) so I figured the extra strain on the drivetrain wasn't warranted.

Also - I thought I could go from Auto or 4H into 4L on the fly. I tried to do it while moving, but the button just kept flashing. I rarely use 4L so have forgotten what it takes to engage. Do I need to be sitting still and in neutral to both engage and disengage with 4L? I'm able to go in/out of 4H while in gear.

[BasicBlack]

Yes you need to be in nuetral to go to 4L. I find when I am going to 4L I take my foot off the brake to give the drivetrain a little more freedom to make the switch, it seems to work good. The manual says it's best to be moving ~1mph when you do this. It helps the differential gears to engage each other better.

[Dale Gribble]

when i am actually off road, i put it in 4 hi and leave it until i need 4lo. but i snow i usually leave it in auto 4x.

never really even thought about using auto off road, but where i go at, you need 4wd most of the time anyway

Not meaning to thread jack but, does using auto 4x in snowy conditions cause any unpredictability with the handling? I've always thought that if it auto engaged 4wheel in the middle of a curve it could cause some unpredictable behavior and put you in a ditch.

[ksukats57]

Not meaning to thread jack but, does using auto 4x in snowy conditions cause any unpredictability with the handling? I've always thought that if it auto engaged 4wheel in the middle of a curve it could cause some unpredictable behavior and put you in a ditch.

I use A4x4 in the snow. Its never kicked in actually driving for me that I could tell, only when coming off a stop, and if youre turning you can just feel it kind of jerk the front wheels when it gets traction but its nothing that would put you in a ditch

[oneloudz71]

Not meaning to thread jack but, does using auto 4x in snowy conditions cause any unpredictability with the handling? I've always thought that if it auto engaged 4wheel in the middle of a curve it could cause some unpredictable behavior and put you in a ditch.

If you are in the middle of a curve and the truck decides it needs to engage 4wheel, you were about to go in the ditch anyway. The only time it will engage 4wheel while in auto is if wheels are slipping. Now I know that you can control a "drift" through a curve and if 4 wheel where to engage then it would screw you up, but if you are driving that way then you shouldn't have it in auto. I drive in snow in auto ALOT and I have never had an unpredictable behavior due to 4wheel kicking in.

[Dale Gribble]

I use A4x4 in the snow. Its never kicked in actually driving for me that I could tell, only when coming off a stop, and if youre turning you can just feel it kind of jerk the front wheels when it gets traction but its nothing that would put you in a ditch


If you are in the middle of a curve and the truck decides it needs to engage 4wheel, you were about to go in the ditch anyway. The only time it will engage 4wheel while in auto is if wheels are slipping. Now I know that you can control a "drift" through a curve and if 4 wheel where to engage then it would screw you up, but if you are driving that way then you shouldn't have it in auto. I drive in snow in auto ALOT and I have never had an unpredictable behavior due to 4wheel kicking in.

Ahh ok thanks for the info... as you know my trucks older and has the floor mounted 4x lever so I'm not really familiar with how the auto system works but what you guys said makes sense... Auto 4x would be nice on take offs. Alot of times when leaving a stop sign I engage 4hi and then disengage once I'm rolling so I can definitely see having the convenience of auto in the snow.

[DMANbluesfreak]

I use A4x4 in the snow. Its never kicked in actually driving for me that I could tell, only when coming off a stop, and if youre turning you can just feel it kind of jerk the front wheels when it gets traction but its nothing that would put you in a ditch

Same for me (rain, not snow). Once I left it in Auto4 when I was trying to fishtail and it just pulls you out of it immediately. The system seems pretty smart to be honest.

The only thing I'd worry about leaving it in Auto4 while offroading is the unnecessary wear you'll get on the front diff actuator (or whatever engages the front wheels) since it'd be engaging and disengaging very frequently. I feel like 4HI would be a better choice.

[DarkCharisma]

Personally I'd select 4Hi and leave it so the clutches aren't locking-unlocking constantly, but it probably won't do any damage with what you're doing now.

[ksukats57]

Yeah offroad i would just leave it in 4hi

[DMANbluesfreak]

Personally I'd select 4Hi and leave it so the clutches aren't locking-unlocking constantly, but it probably won't do any damage with what you're doing now.

Yeah thats what I was thinking...

[chevypower427]

actually, there is a clutch pack inside the transfer case, whenever front and rear propshaft speed is different, tccm sends a signal to the encoder motor to compress clutch pack. i have gone through 3 sets of clutch plates (and i never use auto 4x) before i decided to swap to a np241. i would try to avoid using auto 4x, i suppose using it in the city if its snowy makes sense, but if you dont need 4x leave it in 2wd, it only takes 1/2 a second to engage your 4x4. and yes for 4lo in neutral below 3 mph, as it is an unsynchronized shift.

[smokinsilverado]

Yeah I would just put it in 4hi and if you don't need that leave it in 2wd. If the road isn't that bad that it the truck automatically switches from 2wd to 4wd with it in auto I would think you could make it most of the way in 2wd

[blackbodylift]

Auto 4 is bad. My buddy's 2000 snapped the transfercase retainer from auto 4 IMO it's junk.

[2good2btrue]

Not meaning to thread jack but, does using auto 4x in snowy conditions cause any unpredictability with the handling? I've always thought that if it auto engaged 4wheel in the middle of a curve it could cause some unpredictable behavior and put you in a ditch.

Yes. When I first got my 02 I was on the interstate in the middle of a huge blizzard. There was freezing rain and then 8"+ of snow fell....the plows couldn't keep up. I was THAT guy in the left lane going 75. I'd hit these super slippery spots of ice underneath and in auto 4wd the rear end would spin up instantly....faster then it could engage the front and **** got sketchy real fast. Plus I was fully expecting to grenade something with how hard the auto was engaging. I put it into 4H and it stopped being quirky with the ice spots.....I've never used auto4 since.

[ryepsboe]

when in auto 4x4 your front drivehsaft spins so dont forget about it, or dont leave it on all the time

[Underpowered]

If you are in the middle of a curve and the truck decides it needs to engage 4wheel, you were about to go in the ditch anyway. The only time it will engage 4wheel while in auto is if wheels are slipping. Now I know that you can control a "drift" through a curve and if 4 wheel where to engage then it would screw you up, but if you are driving that way then you shouldn't have it in auto. I drive in snow in auto ALOT and I have never had an unpredictable behavior due to 4wheel kicking in.


:word:

never had any odd behavior due to the auto 4x4.

[seaark17]

I learned something new I thought auto 4x4 and 4Hi did the same thing. I just thought auto was for people that didn't know when or how to use low. So in auto it only kicks in when you need it?

[Underpowered]

I learned something new I thought auto 4x4 and 4Hi did the same thing. I just thought auto was for people that didn't know when or how to use low. So in auto it only kicks in when you need it?

correct. technically it is in 4wd, just the t-case is not engaged. when the truck senses the rear wheels are turning faster than the fronts, it will lock in 4hi basically.

[DMANbluesfreak]

^ Well, actually the T-Case is engaged, but the clutch pack (?) in the front diff isn't engaged. Or is it the other way around?

[Underpowered]

^ Well, actually the T-Case is engaged, but the clutch pack (?) in the front diff isn't engaged. Or is it the other way around?

frond diff is locked in, auto 4x is controlled inside the T-case.

[DMANbluesfreak]

Okay, I always get it mixed up...

[bonedust]

im on my 4th auto4 chevy and Ive never had a problem. i put the truck in auto4 when snow arrives abd take it out when its gone. i dont beat on my stuff unmercifully, and i dont do burnouts, and im decent about regular maintenance...so maybe thats the difference.

[seaark17]

Auto 4 actually sounds smart now that I understand it.

[bonedust]

it is for regular on-road use. it was not built for mudding.

[DMANbluesfreak]

Auto 4 actually sounds smart now that I understand it.

The only downside is the extra rotating mass caused by the front drive shaft being engaged and it reduces fuel economy SLIGHTLY. I figure it's worth it in the rain/snow/etc, but on dry pavement, stick to 2wd.