4x4 binding

Decided to check my 4x4 a couple weeks ago. 4hi engages but the light flashes for a minute or so then goes solid. Disengaging the light just flashes. I have to come to a stop and go in back and forth a fue times to disengage with a very loud bang. Also while driving and coming to a stop if I place the truck in neutral the 4x4 is so bound up it feels like parking drake is set. Any ideas????

 

Are you driving in 4X4 on pavement or other hard dry surfaces? That is a no-no and will cause the entire drive train bind up. You risk breaking expensive parts. Even if it doesn't break right now you are causing excessive wear which will lead to premature parts breakage.

When in 4X4 the transfer case tries to make all 4 wheels turn at the same speed. Which is impossible when cornering where all 4 wheels are taking a different track and need to turn at different speeds. On a slick surface such as mud, snow, gravel, or loose dirt the inside wheels will easily spin slightly and cause no damage. On surfaces with good traction the inside wheels have too much traction and cannot spin putting everything under a lot of stress.

It is best to make the switch from 2hi to 4hi while moving. If stopped there is about a 50/50 chance the gears inside the transfer case will be aligned so the 4X4 can engage. If the wheels are turning the gears will engage when things line up. It is best to go from 4hi to 2hi the same way, while moving.

If going to 4lo it is best to go to 4hi on the move. After 4hi engages stop, shift to neutral or press in the clutch then shift to 4lo. This way you're not asking the transfer case to do 2 things at once. It is possible to go from 2hi straight to 4lo, but I find it better to do it in 2 steps. You may need to let the truck roll slightly in order for the gears to line up.

It is very common for any 4X4 to have difficulty getting out of 4lo. Stop, go to neutral and then shift to 4hi, not 2hi. If it doesn't disengage backing up 10-15' and then pulling forward usually helps, but I've had to do this dance several times, and not just with Tacoma's. Once in 4hi, simply start driving then go back to 2hi on the move.

 

Yes on pavement. Why would it matter. 4hi can be engaged up to 60mph. This never happened untill this year.

 

Don’t use 4x4 on pavement.

 

Mine disengages with a very noticeable bang as well since brand new.

 

I engage my 4x4 once a month and when on pavement I engage it as I'm coming to a stop. When disengaging I do it under deceleration and have never had an issue. It will bang if you are under load, either accelerating or if you are turning, as that binds your front axle and when that lets go, you get the boomshacakalaca

Going on

 

OMG, are you serious? Good luck with that.

 

If your front and back tires are different at all (i.e., some are more worn than others), then it will bind on pavement, even driving straight forward.

 

Toyota recommends in the manual that you drive it in 4wd once a month or so to keep things lubed up. I usually do this on pavement but at lower speeds and on very straight stretches. Once in a blue moon I'll put it in 4lo in my driveway and rock it back and forth a few times just to confirm 4lo is good

Not sure I'm buying that, but I'm not a expert. I think the binding issues would only come up in turns. I don't see diff binding happening over a few 32nds of tire wear.

Generally 4wd should only be used on surfaces with some slip, like off road, snow, etc. The only time I really use 4wd is in the winter when it snows and once or twice when pulling on something with my truck. I'm not an off roader.

Best of luck!

 

Feel free to buy whatever you want.
Doesn't change physics.

 

It's not the end of the world if you engage it on pavement occasionally. Just go easy on it. When the highway is mixed ice and dry road I run at highway speeds in 4x4 for extended distances. Been doing this with all my trucks for decades. No issues.

 

It does happen. Seen it first hand. Seemed the late 90’s early 2000 pathfinders were very sensitive to a variation in tread depth.

 

Do you use it on regular basis? Engage it every month or so to keep everything lubed and unstuck? Mine engages and disengages with out much fanfare now. I'll engage it every month, sometimes on dry pavement going straight and it drives fine. I disengage it before turning on pavement.

 

that has nothing to do with why it's not okay to use it on pavement...you have a part time 4x4 system, not a full time 4x4 or AWD system. AWD/full time 4x4's have a center differential which allows the front/rear drivetrain to move at different speeds and prevent bind up. You do not have a center diff, only a transfer case and thus turning on dry pavement will bind up your front drivetrain. Turning on snow/dirt/gravel etc in 4wd allows the wheels to slip if they need to which is why it's safe to use on those surfaces.

You can drive on dry pavement with your truck if you do it in a straight line, or keep it as straight as possible. Abrupt turns or sharp turns though are no good. If you're lucky you'll just break a CV axle doing it, if you're not so lucky you'll break something much more expensive.

 

I did a little online research and while that sure as hell still doesn't make me an expert, it seems some AWD and 4WD systems ARE sensitive to under/over inflated tires and tread wear.

However not ALL are, and it seems mostly it is the early 4WD systems and AWD systems and some specific makes and models are the ones that are.

Still, I stand SEMI-corrected. I acknowledge that tire wear and inflation issues can have a negative impact on some 4WD and AWD systems and I had no idea that was a thing until now so thanks for those that pointed it out!

I say semi-corrected though because I'm still not convinced it's a problem for our trucks going in 4WD in a straight line at reasonable speed even on dry pavement.

I did some reading in my bible (owner's manual) and there are no cautions about this in the tire section or in the 4WD section or anywhere else that I can find (PDF search). It just states to drive it about 10 miles in 4WD every month to keep things lubed. It seems to me, as much as Yota likes to warn us not to do this or that and the other that if there was a likely issue, they'd put a warning in there if it was a problem. It would give them another opportunity to deny doing any warranty work!

I'm sure people that sell tires and tire services will tell you this no matter what kind of 4WD you have, because they sell tires and tire services.

I have been driving my truck in 4W HI about 10 plus miles in a straight line on pavement (and occasionally using it for it's intended purpose) since I purchased it in November of 2008... when I remember to do so. Let's say I've remembered about half the time.. that's a total of about 60 times and about 600 miles in the last 10 years? Maybe a little more, maybe a little less. So far I haven't broken anything and when I changed the diff greases and changed the ATF filter and did a DIY flush I didn't see anything concerning in the fluids. That's not to say that I might not be doing some premature wear but... I'm going by what the owner's manual says and I'll probably keep doing that since that is what the owner's manual is for.

That's why we each have our own truck though, I'm not telling y'all how to treat yours.

However you treat your truck, best of luck with it!

 

There are different ways that a vehicle can be deemed "sensitive" to varying wheel circumferences. Most particularly, for AWD vehicles. Differing circumferences will cause a continual "drift" in the center differential. If the center differential has a frictional coupler, then even minor differences in the speed of the two outputs will wear that coupler. Other vehicles, for instance, a Subaru with a viscous coupler, will be most sensitive if the difference in diameter is extreme like you would get when mixing tire sizes. Vehicles with open center differentials will be extremely NON-sensitive to varying circumferences, since the difference will be below the threshold at which the computer detects slip.

Now 4WD vehicles could be deemed sensitive or insensitive in very different ways than AWD vehicles. AWD vehicles, by their very nature, will allow differing speeds for the two outputs, so handling will not be affected, but longevity will be, but 4WD vehicles will absolutely not allow *any* variance in the output speed whatsoever, unless you actually break something. That means that the ONLY mechanism by which the variance can be released, is by slipping a wheel with respect to the surface of the road. Longevity (mechanically) will probably not be significantly affected (although the tires themselves will wear much more quickly), but handling will be hit very hard.

Generally, 4x4 vehicles are considered LESS sensitive to variations in wheel circumference, HOWEVER, this is because 4x4 vehicles are *normally* operated in 2WD. In 2WD, vehicles are *completely insensitive* to this variation. In fact, you can put on 4 very difference sizes of wheels and it will probably drive ok in 2WD. This is not the case while in 4WD.

A 30 inch wheel has a circumference of 94.247779608 inches (30 * pi).
A 30 1/8 inch wheel is 94.640478689.
The difference is 0.392699081 inches.
What that means is that with treads worn down such that the two axles have an average tread depth difference of just 1/16th of an inch (top and bottom, 1/16 + 1/16 = 1/8), TWO wheels will have to slip 0.39 inches for EVERY REVOLUTION, or 1 wheel will have to slip 0.79 inches per revolution.

And let me reiterate... that is for just ONE go-around.

You *might* have enough slack in your driveline to soak that up for one revolution, but not for 2.

If the total difference is 1/16 (1/32 + 1/32), the per-revolution slip falls to "only" 0.196349541 inches. But after a few revolutions, it still adds up.

 

Is this across the left and right side of the front or back only, or across any of the tires including diagonally? E.g. is it less problematic if the rear tires are worn more than the front but worn roughly evenly from left to right on both the front and back, or equally problematic? Does that question make sense?

Thanks!

 

I would always run the best tires on the rear if you are in that situation...your rear is always in drive no matter 2wd or 4x4. I had a blown tire out on a remote trail once and only had a smaller spare on me (32" spare and the rest of the tires were 33s). I put the mismatched tires up front so both the rears matched. My 4x4 still worked fine offroad and I didn't have to worry about messing up the rear drivetrain on the highway to get home.

 

Yeah I get that your driven tires should be the ones with more meat on them, I'm more just wondering about the whole tire wear mismatch question in general, like conceptually and whether it's a side to side, or front to back, or all of the above issue.

 

mine clunks pretty hard sometimes too disengaging, try greasing your prop shaft. disengaging it under load is going to make a nice clunk also so I wouldn't try that too often either