Another 4 Wheel Drive Question
- Thread starter CoastieRon
- Start date
nope
Like it was discussed earlier, the Limited models that come with Full-time 4wd have a center diff which allows the front and rear wheels to spin at different speeds, so there is no risk of drivetrain binding. Those models, unlike the SR5 and Trail and TRD with part-time 4wd, were actually designed to operate 4wd all the time (including on pavement).
The link here does a good job of explaining the nuances of part-time 4wd versus full-time:
4WD Simplified Version 4.0
wfo9
New member
Just to clarify, the Toyota literature is there to make it idiot proof. People who have no mechanical understanding or awareness of what the vehicle is actually doing while driving it (80% of 4 runner owners) should follow those instructions. It's there as fire and forget type advice.
I've driven my 4runner in 4h for hundreds of miles (500+ to be exact) on perfectly dry pavement with 0 binding. Why? I was breaking in my gears. But I did use the technique of going back to 2h for sharp (under 20mph turns). I actually had to think about what I was doing while driving (imagine that)
For heavy off-road use. It's important to understand the 4wd system and all of its weak points before you mash the throttle... (as slow as possible as fast as necessary....)
As far as less stress offroad goes... You are way oversimplifying it. Sure, a dirt or muddy/snowy road will allow for the axles to spin at uneven rates with less stress, but that is just one of many scenarios encountered. Take something like Moab... That stuff can have way more traction than any road surface and the center diff will see extreme stress. There are many types of terrain and situations that create lots of binding stress off-road.
You are much better off trying to keep your wheels as straight as possible while climbing difficult obstacles, but that has more to do with the CV axles and how much vulnerable they are at angles than any drive-line binding.
In summary, don't just drive around in 4h on dry pavement. But if you need to keep the t-case chain lubed up (because you have no time to go offroad) and you actually have a brain and can pay attention to what you are doing, it can be done on dry pavement without any issue.
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amicalola-man
New member
The big difference here is the speed at which the driver is taking turns and putting the wheels in a bind. Not sure about everyone else but I don't wheel at highway speeds. Sure you can do turns in 4wd and it shouldn't hurt anything, however repeated abuse can cause damage, and I for one didn't spend that much $$ for a truck to risk damaging. Especially if it can be prevented. The OP has very limited knowledge about part time 4wd systems and we can't just say just put it in gear and run it.
Again, is everyone here so insecure about themselves that we have to constantly fight?
I agree with most of what you are saying here. And yes I did somewhat oversimplify the drivetrain stress issue on dry road and off-road because I didn't want to give a complicated answer to what was a very straight forward question from the OP.
I will say in regards to drivetrain binding in rocky terrain, like Moab, binding is still not very likely as it is on dry pavement. Sandy/dirty rock surfaces, uneven surfaces where certain wheels lose ground contact, ect. I just don't see there being quite the same amounts of stress as there are on-road.
Sure, if you found a flat and straight piece of rock and started doing repeated K-turns in 4wd mode, you might start to induce some stress (at that point, I would probably switch back into 2wd). But in general, off-road (even on rocks) the wheels have less traction and thus less stress for the whole 4wd system.
wfo9
New member
Respectfully disagree. In an oversimplified world yes, in the real world on very rough and rocky terrain it does not happen that way. Just the fact that you are in 4Lo increases tq load potential quite a bit, then you have all the spinning and catching with lots of dynamic loads... These are generally things you try to avoid, but it does happen.
The stresses on the center diff off-road are much more extreme than anything you could ever induce in normal on-road driving conditions.
buffalojay
New member
I'd just like to say thanks to all for the info! I didn't even know that you should drive it in 4Hi once a month! Luckily I live not to far from some dirt roads so shouldn't be too big of a deal. Thanks for the info guys.
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jwkilgore
New member
My understanding that not driving in 4WD was a safety issue and not a damage issue. If you are driving around sharp corners at the max speed for those corners (say, a twisty mountain road with 180° hairpins), having the drive train start to bind up could cause you to lose control. I encountered this the very first time I drove my 4Runner on the test drive. I put it in 4Hi just to try it out, and left it there. When taking the sharp turn back into the dealer parking lot it started fighting me and I had to straighten back out sooner than I wanted.
But I would hope the drive train components would be strong enough that, even with sticky rubber tires on sticky 150° dry pavement, a tire would slip before something broke.
That said, driving around paved curves in 4WD can't do any good for your system, so I'd avoid it. If you absolutely can't find a gravel road or parking lot, I'd find a nice straight paved road for the occasional 4WD lube.
But I would hope the drive train components would be strong enough that, even with sticky rubber tires on sticky 150° dry pavement, a tire would slip before something broke.
That said, driving around paved curves in 4WD can't do any good for your system, so I'd avoid it. If you absolutely can't find a gravel road or parking lot, I'd find a nice straight paved road for the occasional 4WD lube.
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Here's what my manual says:
You should drive in four-wheel drive for at least 10 miles (16km) each month. This will assure that the front drive components are lubricated.
This is from a manual that has a couple of pages on how to tighten a gas cap.
I'm pretty sure driving 10 miles in H4 on drive pavement isn't going to harm my 4Runner. I'm equally sure that H4 should be used primarily in off-road/icy/snow-covered adventures (that's in the manual too).
Now, who wants the first hug?
You should drive in four-wheel drive for at least 10 miles (16km) each month. This will assure that the front drive components are lubricated.
This is from a manual that has a couple of pages on how to tighten a gas cap.
I'm pretty sure driving 10 miles in H4 on drive pavement isn't going to harm my 4Runner. I'm equally sure that H4 should be used primarily in off-road/icy/snow-covered adventures (that's in the manual too).
Now, who wants the first hug?
off-road runner
New member
I use 4hi regularly for 6-7 months out of the year. Those other 5-6 It rarely sees 4x4 but as toyota recommends, it is a good idea to "exercise" those components. If you forget to or don't get the chance to engage in 4x4 for a few months or so I highly doubt it will suffer any damage. And if you never need to engage it a few times a year... you don't need a 4wd.
If you must engage/disengage on pavement, personally I prefer to be going < 45mph and have my foot off the gas pedal. As others have said, probably not a good idea to do figure 8's in the parking lots.
If you must engage/disengage on pavement, personally I prefer to be going < 45mph and have my foot off the gas pedal. As others have said, probably not a good idea to do figure 8's in the parking lots.
Thanks for letting me know the discussion ended...for you. There were 6 posts after your final entry. I appreciate your welcome and support.
Maybe this would be worth starting another thread over, but I'm not following what you're saying here. What do you mean by dynamic loads on off-road terrain? And where, besides Moab, are you driving over long stretches of clean rocky surfaces? What does driving in 4Lo have to do with undue stress on the 4wd system? I'm not trying to disprove what you're saying, I'm just trying to get some clarification on what you are saying.
You can hear when drivetrain binding is occurring. You don't necessarily hear the drivetrain itself getting messed up or stressed; rather you can hear the inside tires skip/stutter when you make a sharp turn with 4wd engaged on dry pavement. I've driven on dry rock surfaces before (though not Moab) and have yet to hear those same sounds I heard when I drove on dry pavement.
Jeremy556
New member
In 4lo there is more torque applied to the drive line. It isn't uncommon to be spinning tires, or for a tire to be spinning in the air, then abruptly regain traction. You are also likely aired down and your tires have far more grip at 12psi than at 40.
On slick rock, you feel binding and tires bark loudly, often.
wfo9
New member
No limit really, Just shift to and from below ~40mph.
wfo9
New member
^^^ what he said. Those little noises you hear on drive pavement are nothing like the dynamic loads in rock crawling situations. Add in lockers/Atrack... and you have multiplied the traction potential and binding loads and yet it typically holds together just fine.
Again. smart drivers do everything possible to mitigate the loads, but sometimes there is no way to avoid it.
I have yet to see a TCase bust on a 120/150. CVs and rear thirds are common. The only reason the front diff does not blow all the time is that the CVs are so incredibly weak in comparison. The TCase is the least of your worries....
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whodat
New member
I had it in 4HI towing a Uhaul from Texas to Iowa (over 700 miles) at highway speeds, and that was 3-4 years ago. During the trip, I was pulling out of the gas station making a sharp turn and the grinding noise kicked in, oops! To this day, the 4R is still fine.
Edit: forgot to mention the roads were dry (was in 4hi because 4hi seemed more stable to me with all the crosswinds, no proof behind that, just my opinion)
Edit: forgot to mention the roads were dry (was in 4hi because 4hi seemed more stable to me with all the crosswinds, no proof behind that, just my opinion)
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CoastieRon
New member
I can't believe the pot that I stirred lol. I appreciate everyone's insight on this.
