Truck in question is my '91 Pickup deluxe, 4wd.

Ok, I'm pretty savvy with engines/vehicles and everything, but it just so happens that I don't know much about 4x4ing!

So here are the simple questions:

4H is for creeping down hills to pace yourself?
4L is for crawling over sand/up hills?

What should I use 2H for?

Also, can I engage 4wd without locking the hubs to give
myself positive traction on the rear end only?

And last, why am I supposed to drive in reverse a few feet, and then spin my tires forward once i'm out of 4wd, and unlocked the hubs?

thanks for any tips.

 

Hey frozenwave, one of the first things you might do to increase your understanding is to look on Howstuffworks.com. Check out 4 wheel drive, differentials, etc. You're an engine guy, so once you understand the hardware you'll have it figured out!

 

lol allright i guess ill answer this one...2hi is for general driving, and if your in a snowy area you can use 4Hi for more traction while driving at normal speeds (below 55), and 4Lo is for creeping around as it uses a gear reduction to keep you slower, so you wanna use this option for climbing up hills, or if you were stuck in 2HI you would want to lock it in 4Lo to get out, 2Hi is your 2 rear wheels driving and 4Hi is all 4 of your wheels driving, locking the truck into 4Hi without locking in your front hubs does nothing for more traction out of the rear, hope this helps...also in the future use the search device

 

so if im having light traction troubles driving up hill, 2Hi is fine right? but should i still roll back, then spin the tires forward when i come out? why do i have to do this?

 

Well a little more info would be good...but I'll go with what I know and what you have posted.

4H is for about anywhere, up here I use it mainly in winter. Going to and from where I need to go.
4L I use for off road, I don't go real fast nor do I see a reason to. If you need to you can use 4H to get from mud hole to rocks then I'd go back to low. That's me playing with my pickup 22re 5spd. Low is to keep the RPM's up and moving slow enough not to spin or so you don't smoke a clutch.

Going into 4H and not locking the hubs is as useless at t!ts on a bull (been wanting to say that for a while). I'm assuming you have manual hubs now. So once you unlock them you are out of 4wd. No need to go backward, unless something is bound and you can't get into 2wd. You can however go into 4L and be unlocked just to go slower, but you really don't need that.

 

I'm not understanding this...

Wow you guys beat me quick while I was typing it up..

 

Meh, you can drive over 55 in 4wd. I used to do it daily going to and from school. Its just not recommended ...nor is it recommended to SHIFT into 4wd over 55mph.

You would only have to go backwards if you had auto-hubs (different from ADD, which you could have) Auto-hubs were available only from like '84-'88 or so.

 

I know there probably different, I'm not sure how the older ones were. My 95 Runner I don't have to go backwards. But with saying that my grandfather had an early 80 Dodge and you had to go backward 10 feet to unlock after being in 4wd. So I can see his thinking.

 

Your '95 has "ADD", Attention Deffic......er....Automatic Disengaging (or Disconnecting) Differential. Auto-hubs you have to drive in reverse to engage and disengage 4wd, I do believe.

 

ok thanks guys. the backward thing i see everyone do that has locking hubs. after they unlock the hubs and come outta 4wd, they say you're supposed to roll back a complete turn and then spin the tired forward for the safety of the trasnfer case or somthin. thanks guys.

 

oh. Probably because the driveline(s) can bind up and its just easier on stuff if you get rid of some of that tension. By driving a little in reverse, it helps to relieve some. Its not really necessary, but if you drive on a non-slip surface in 4wd like concrete (NOT RECOMMENDED), then you should do so.

 

are 4wd and 4x4 actually different? i see them labeled on some many trucks differently, like they actually are.

 

Typically no. But 4wd is sometimes referred to in the "All Wheel Drive" (AWD) form. 4x4 is like 99.99% used to designate selectable 4wd

 

AWD generally refers to full time 4WD, the kind of vehicle that's OK to drive in 4WD on dry pavement. In regular 4WD vehicles that's not OK, it will put a lot of stress on the drivetrain if the wheels can't slip a little.

 

yes. AWD is full-time 4wd.

its not that the wheels can't slip (they can due to the differentials) but since there is not a center differential (between front and rear driveshafts) you get binding in the T-case because the shafts want to turn at the same speed.

 

Because there's no T-case differential, the wheels are being turned at the same speed. When you go around a curve, the wheels would normally go at different speeds. Thus the binding. But if the wheels could slip against the ground, they could turn at the same speed so there'd be no binding.

 

OK, i thought they were somehow different. (4x4 versus 4wd)

 

if you use your truck to pull anything sometimes it helps to put it in 4H if your going up steep hill to give you more traction

 

2H (2 wheel drive, high range) normal everyday driving, pavement, concrete, hard surfaces, ...

4H (4 wheel drive, high range) lower traction situations, gravel, dirt, snow, ...

N (neutral) no power to the wheels

4L (4 wheel drive, low range) low traction situations where more torque (power) or control is needed, like crawling, and pulling, ...

If you have ADD, all you have to do is pull the lever for high range as long as you are below 50-55 MPH, to go into low range it is a good idea to stop and put the transmission in neutral before shifting into low range.

If you have locking hubs out at the wheels they will first have to be turned to the "lock" position, attempting to pull the lever before locking the hubs, and while moving, will result in grinding the transfer case gears, also not locking the hubs will result in 2 wheel drive no matter what the indicator in the truck says, I sometimes use this to my advantage (leaving the hubs in the free position) and shifting into 4L essentially giving me low range and only 2 wheel drive to have more control while backing a trailer.

 

i rarely use 4hi... unless i'm driving on snow covered highway..... if i need 4 wheels to have power, i need the lower gears to go slow.. if i am jumping from trail to trail, i shift back to 2hi.

"free" hubs and 4lo is a cheap trick to get 2lo without a twinstick setup...

if you need more traction beyond what 4lo can give you try putting a locker in the rear.