How do I use 4WD and not destroy my truck?

It's a decision that people will have to make. Personally, after looking at the mechanics of it, the risk is minimal if driven straight for a short period.

 

You're not going to grenade your 4wd system if you engage it on a dry road and drive a mile.. unless it's got some gnarly switch backs or sharp turns. I usually just engage my 4wd twice a month when headed out for an errand, from the end of the drive way until I make the turn onto the main road. Is it perfectly straight? No- there are some turns, but nothing that gives the 4wd system any binding issues.

The bottom line here is, you can feel the binding happen- if it does reassess what you're doing, regardless of he surface. And just don't be stupid- don't engage 4wd in the parking lot and try to make tight turns.

 

I always try to take an opportunity when it rains or on long straights to engage 4hi once a month (the manual says you should do like 6-10 miles a month, can’t remember specifically). Ideally you want to heat up the gear oil in the front diff.

Also I second breaking down a tight turn into a few points whenever I’m 4wd, even if in the snow or mud/gravel. Figure if you’re using 4wd on slippery terrain you’re probably not in a massive rush anyway, so might as well take the extra time to avoid binding. You’ll feel the front end become unhappy through your steering wheel in any case.

I like to engage the locker from time to time but from what I understand the locker is simply there to get you unstuck, ideally with front wheels dead straight. As others said the system is pretty robust and hard to abuse. Find an empty dirt lot after the rain and toy around with your system. Fun fact: I didn’t know the rear locker wouldn’t engage unless you’re in 4lo for the first 2 years I owned my truck

 

Yeah... probably ok if nothing offroad is close by. I guess i'm spoiled with hundreds of miles of dirt roads 10 minutes away and forget that's not always the case.

 

I saw the same thing at first: WD40.
Lol

 

I've forget on more than one occasion to shift out of 4wd after coming out of the woods and onto asphalt, didn't notice for several miles.Trucks still in one piece but yeah I wouldn't make a habit of it.

 

True, but if you know how 4wd works on a mechanical level, it’s pretty clear why it’s okay, but you won’t find that kind of nuance in a manual. That’s why we have forums

 

It's just easier for the manual to say "don't do it", "only on low traction" and thereby avoid any liability entirely. If they say you can do it on a straight dry paved road, someone with 3 different sized tires on their truck will try it, blow up their drive train and then try and sue

 

Bold of you to assume anyone with 3 different size tires is reading the manual

 

If they knew how to read they'd be very upset by this

 

So, how do I use the 4WD without destroying something?

1. I understand tight turns should not be made in 4WD. Will my turning radius be restricted or will I physically be able to turn tight and end up grinding something up? -You can physically force it to turn with 4wd engaged in high traction environments (i.e. pavement). You will feel it (the steering and drivetrain) bind and fight you to go back to straight. This is your ideal limit. If you feel that, dont turn as tight, or take it out of 4wd. Try it in a parking lot and get the feel for it. You will not damage anything just engaging it and trying it and turning it off.
2. What's considered a "safe" turn? 45 degrees? -see above. then the drive train binds. The angle is irrelevant. Pay attention to what the truck does and how the wheel feels
3. What about with lockers on? Should I turn even less? -You can turn your rear locker on (assuming you only have a rear?) and drive around all day on dry ass pavement if you want. You're not going to damage anything except wear your tires down faster as they chirp and skip through the turns
4. Does this apply anywhere or only on flat, smooth surfaces? I.e. If I'm on a bumpy, soft, sandy road, can I turn any tighter? -The less traction you have the less bind you will feel in the driveline/steering. If you're on a snow covered road you can crank the wheel as hard as you want and mash the gas and it probably wont bind, the tires will just spin. Again, given the terrain and amount of traction you have, you will need to pay attention to what the truck feels like. Note: this is where you have to learn how your truck works in off road environments. If you have the wheels cranked and you're on the gas with little/no traction (trying to get over a rock or get out of a ditch), and you suddenly grab traction (on the front tires for example) that sudden addition of traction under power could cause damage, like snap your cv axles (which are weaker the harder they are cranked in a turn) or in rare cases bent a tie rod end and fuck up your steering, or other less likley things. All of this us not likely to happen unless you start throwing large tires on the truck and really getting into hard situations. A mostly unmodified truck on a normal dirt/gravel roads...youll be fine. dont worry about it.
5. The manual says can go from H2 to H4 if under 25mph. I tried that once at about 5mph and got a terrible grinding noise. Is something wrong? -you can shift from 2wd to 4hi at basically any speed, just let off the gas. No way im slowing to 25 on a highway with snow on it just to shift into 4, ill throw that bitch into 4hi at 45-50 and carry on my merry way. Do you have a J shift (lever with knob) or e shift (lever with a button) on your truck? If you have a j shift, and you are getting grinding going fro 2-4hi EITHER: your t case is in fact broken, or more likely you're shifting past 4hi and trying to go into 4lo. When you let off the gas, you should not get any grinding going from 2 to 4hi. In a j shift, you pull the lever back torward you, thats it. To go to 4lo, you need to be in N, and you pull the lever back toward you, over to the right, and push it back forward, then put the truck back in drive.

Thanks for your patience and humoring my anxiety!

 

Why is it ok? I've always read otherwise.

 

Not sure if you're being serious or not.. but at a mechanical level, its ok to drive in 4wd in a fairly straight line on pavement because you're not creating enough differential between the front and rear "paths". It's only when the front or rear needs to rotate at a different rate do you get the binding. The transfer case is essentially a locked diff at that point being in 2wd vs 4wd is just sending power to one or both axle shafts (drive shafts). Same with a locker- locked on pavement is fine until you start turning and one wheel wants to turn at a different rate than the other. In an open diff this is fine, but with a locker, the same binding occurs, and one tire will chirp as it tries to catch up to the other.

 

wasn't there a thread on here a year or so back about a guy that blew up his t-case and had all kinds of carnage because he was cruising on the highway in 4wd during snowy conditions, but it was determined he had different sized tires on front/rear? Or am I misremembering that

the carnage was pretty epic, I remember that much. I think he eventually got it all repaired though.

 

With a J-shifter and a manual transmission you can go in and out of 4lo on the fly.

Shifting from 4lo to 4hi on the fly is pretty easy. Goes in easier if you double clutch, but it's not necessary. I do it all the time.

Going from 4hi to 4lo is harder to do on the fly. You have to be going real slow for it to work, and you have to get the RPM's just right. Usually not worth the effort.

 

I've seen it happen before- someone I knew after high school- bought two new different (lets say 31 vs 32) size tires and put them rear of his jeep to save a few bucks. The first snowstorm that season, he puts in 4wd, and the case blew up.

 

Definitely makes me want to check my tire pressure more regularly lol. I think the difference would have to be pretty severe to cause issue right away, but the guy I mentioned the size difference wasn't great but he had been driving for several hours if I recall correct.

 

the guy is asking how 4wd works, and if he can make tight turns in 4wd on pavement...so telling him he can shift from 4hi to 4lo if he rev matches just right is probably a bit above his pay grade, and not very pertinent or useful information for him. If there's anything he should avoid doing to prevent damage to his 4wd system, it would be what you have suggested lol. But thanks for the technical clarification

 

You make a good point. I agree.

 

It's a sad waste of a very capable 4wd vehicle that isn't off road for at least 6-10 miles a month in the normal course of driving. I don't want to know what percentage of these trucks this applies to, probably 90+%.