4WD Auto vs 4WD High?

[Nitro]

TFL leaked this interior photo a few months back showing the different drive modes. What would be the difference between 4WD auto and 4WD High? Is the 4WD auto similar to all wheel drive?

 

[ShesaRunner]

Auto must be like on my work Tahoe, it kicks in the front axle as needed and otherwise is in 2wd. That works well for occasional snow and mud. For worse conditions (or better depending upon your perspective) 4wd locks in the transfer case/front axle.

 

[RallyKid]

Sorry to revive this old thread.

My wife drove in 4WD High for a couple of months instead of 4WD Auto. What's the difference and could there be any damage to the differentials and transfer case?

I tried searching the forum but it doesn't 4WD cuz it's too short.

 

[ParadigmDawg]

Sorry to revive this old thread.

My wife drove in 4WD High for a couple of months instead of 4WD Auto. What's the difference and could there be any damage to the differentials and transfer case?

I tried searching the forum but it doesn't 4WD cuz it's too short.

I don't think you hurt anything

 

[TRXNUT]

In traditional 4x4 trucks driving on 4HI on dry roads is not good, Driving above 50mph in 4HI on dry roads like on the interstates is even worse. I would definitely have all the fluids changed in the diff's and tranny flush along with an oil change. I'm not a pro to say it's fine so maybe a tech can chime in on this for you?

 

[GC34]

Per the manual
4WD High
Four-Wheel Drive High Range — This range
provides torque to the front driveshaft (engages
four-wheel drive) which allows front and rear
wheels to spin at the same speed. This provides
additional traction for loose or slippery road
surfaces only. The use of 4WD High on dry
paved surfaces will increase tire wear and may
cause damage to driveline components.

 

[Huckle Monster]

Sorry to revive this old thread.

My wife drove in 4WD High for a couple of months instead of 4WD Auto. What's the difference and could there be any damage to the differentials and transfer case?

I tried searching the forum but it doesn't 4WD cuz it's too short.

The difference is... she should be sleeping on the couch tonight....



kidding

 

[ParadigmDawg]

The difference is... she should be sleeping on the couch tonight....



kidding

I don't think that's would hurt anything either.

 

[ParadigmDawg]

Per the manual
4WD High
Four-Wheel Drive High Range — This range
provides torque to the front driveshaft (engages
four-wheel drive) which allows front and rear
wheels to spin at the same speed. This provides
additional traction for loose or slippery road
surfaces only. The use of 4WD High on dry
paved surfaces will increase tire wear and may
cause damage to driveline components.

I don't see how this comes into play with an open differential and we don't even have a locking front. We basically have 3 wheel drives.

I am by no means an expert, I am a car guy, not a truck guy...just trying to use logic.

 

[GP4L]

I don't see how this comes into play with an open differential and we don't even have a locking front. We basically have 3 wheel drives.

I am by no means an expert, I am a car guy, not a truck guy...just trying to use logic.

The open front diff doesn't matter. Just like what the left and right wheels need when turning (especially tight turns, like in parking lots etc), the front and rear driveshafts also needs the ability to relatively vary in speed from one another - that's what 4 Auto mode allows in the BW 48-13 (it's not a center differential), so it can be in "4WD" full-time. 4HI locks it up full time - meant to be used in conditions that require a locked 50/50 F/R torque split. Throw your TRX in 4HI and do a low-speed min-radius turn on dry pavement... Even without the rear axle locked, you'll feel it drag significantly, unlike when it's in auto.

 

[ParadigmDawg]

The open front diff doesn't matter. Just like what the left and right wheels need when turning (especially tight turns, like in parking lots etc), the front and rear driveshafts also needs the ability to relatively vary in speed from one another - that's what 4 Auto mode allows in the BW 48-13 (it's not a center differential), so it can be in "4WD" full-time. 4HI locks it up full time - meant to be used in conditions that require a locked 50/50 F/R torque split. Throw your TRX in 4HI and do a low-speed min-radius turn on dry pavement... Even without the rear axle locked, you'll feel it drag significantly, unlike when it's in auto.

Got it, thanks for the info.

I have had modded sports cars/SUVs for the past 20 or 25 years. I did have a 4x4 truck in 1979.

 

[RallyKid]

Thanks for all of the info. Time for fluid changes and monitoring.

 

[Airmousam]

I have a 21 powerwagon and was bummed I did not have a 4wd auto anymore and had a similar question...this was a couple of years ago...guy chimed in, said he was an engineer for ram ( or a pastry chef or stripper...it is the internet)..claimed they ran the 2500 drive train to 60k miles dry pavement in 4wd, and not to worry...who knows...dude seemed legit..

 

[The dude]

Go back into a tight parking spot on dry pavement and then come back and say it will be ok for 60k miles. When you bind up the drivetrain doing that it and it snaps/pops a tire free to release the tension it hurts.

 

[Airmousam]

Dude (see what I did there) I don't give single shit man..stating what I heard..what I won't do for sure dude is back into a tight spot on dry pavement in 4wd in a 2500...who the fuck would do that? He talked about endurance testing, not being a pinhead.

 

[ParadigmDawg]

I am curious why the wife would hit any buttons on truck if she didn't know what they did. I would think she would just start it and drive off. I do realize it's impossible to say what a wife is going to do.

Did she ever complain on how it drove or turned?

 

[RallyKid]

I realize now i probably should have left the wife part out of it. The TRX is her truck and she’s not a total newb at this stuff.

She never complained about tight cornering, steering or differential noises.

I’m actually thinking it might have been delivered by the dealer in 4WD high.

 

[ParadigmDawg]

I realize now i probably should have left the wife part out of it. The TRX is her truck and she’s not a total newb at this stuff.

She never complained about tight cornering, steering or differential noises.

I’m actually thinking it might have been delivered by the dealer in 4WD high.

When you turn off the truck it would restart in 4 AUTO. I bet the last person in it, hit the 4 high button and it was never really driven in that mode.

 

[RallyKid]

When you turn off the truck it would restart in 4 AUTO. I bet the last person in it, hit the 4 high button and it was never really driven in that mode.

I would have expected the same thing except I tested this assumption last week and again this morning.
It starts back up in 4 High. I tried shutting off for a few minutes and then shutting off for a few hours and same result. I tried being in Auto mode vs custom or baja and same result as well.

 

[ParadigmDawg]

I would have expected the same thing except I tested this assumption last week and again this morning.
It starts back up in 4 High. I tried shutting off for a few minutes and then shutting off for a few hours and same result. I tried being in Auto mode vs custom or baja and same result as well.

Then the truck is broken....

I don't know this for certain but I have never been in 4H. I have been in 4L a bunch but I always take it out of it when I air back up