4wd binding bad with tires turned 15 degrees

Can be dangerous on stock drivetrains, though. It more than doubles the torque applied after the transfer case. It would be pretty easy to break something when you can send roughly 10,600 ft-lbs of torque through the rear axle.

 

Think about this for a moment please. In real world context. I'll wait.

 

Stock first gear(Hi range) in my 6spd is way to fast. Would love to have 2-lo. Keep waiting to find a mod. Preferably one that's as easy as the ABS kill switch.

 

Dude put it up a while back.

Ironically, he's the brother of a former co-worker of mine in the town I used to live in. Had a nice Tacoma at the time, and did this mod for boat-ramp purposes.

I haven't checked in with them in a few months. I should.

I've seen too many gremlins. I ain't fuckin' with it. That's also why I set up all my aux-electrical as basically a separate system from the rest of the truck.

 

Not really. When you put a crawl box in front of your t case and it has 4.7 gears, your more than quadrupling the torque to your rear wheels with just the crawl box alone. If you have a twin stick at the t case and you put that in lo gear it gets insane lo. But here is the kicker. CONTROL!!! What every one fails to realize, even some of those who build these things, is that everything is moving slower. There is no longer the sudden applied pressure that causes breakage. I've heard the "don't put a crawl box with 4.7 gears in front of the t case because of all the added torque in front of the t case" matra for years. I say B.S.!!! I've had this set up and sell this setup for more than five years now in my truck and haven't broken anything down stream, or up stream for that matter with it. Not to mention all the stock drive train trucks I've either sold this to or installed.

As long as you don't bind up anything, or start hopping when going up obsticles, you should be fine.

 

Why would you be binding at all? First of all, if you have open diffs, the moment one tire at either axle gets traction, the opposing tire will get all the power and vice versa. Not to mention these trucks were designed to be driven on the road in 4wd. the 4Runners with the V8 are full time 4wd. true, they have a center diff lock but they can and do get driven with it locked on dry pavemnet.

You've got another issue going on if your having binding issue's at all.

 

Your wrong. these trucks were designed to use 4wd on dry surfaces. not to mention you have an open diff at both ends that is designed to allow one tire to move at a different speed than the other. thus the reason for open diffs.

I run my truck on dry pavement with the front hubs locked and in 4wd all the time without a binding issue at all. he's got internal problems in his front diff or he has a locker in his front diff.

 

Bingo!!!

 

Wouldn't that be AWD? Not jacking, just curious, consensus is don't use 4wd on dry pavement

 

Sort of. most AWD systems use a center diff lock in the transfer case. That system allows more power to be applied front or rear depending on traction. Then if you want true 4wd like our trucks you lock the center diff and equal power goes front and back.

 

So my real world context is based on 40+ rock-crawling competitions with 6 first place finishes in a highly modified CJ-5 that was running a divorced twin stick NP205 behind a crawler box. The rock-crawling world is full of twin stick transfer cases because it is important to be able to turn around a very small radius turn as quickly as possible. So while crawlers will normally run in 4Lo-locked at all times, they use the twin stick to quickly drop the front axle from the drive train to make a sharp turn. I have seen many times a competitor (including myself) forget to lock the transfer case back in after a turn and start attempting an obstacle only to grenade something in the rear axle. Usually it is a ring and pinion, but axle shafts can snap also.

So my basic point was, be careful. It is a fact that running in low range without the front axle does put additional strain on the rear components. You could run this setup and never have a problem, but it does increase the risk of breaking something.

My point exactly. If you're careful then you should be fine. For me on typical trails, if it is bad enough to need low range then it might as well be 4L. It reduces the risk of anything breaking.

Okay, now I am concerned that a vendor who sells driveline parts is providing this kind of misinformation. The 4Runners are set up entirely different from Tacomas. They use a lockable center viscous differential so that the front driveline can turn a different speed from the rear. Tacomas do not have a center differential. The transfer case is either locked or unlocked. In a turn (no matter how shallow) the front must turn a different speed from the rear or it will need to make up the difference by skidding (thus the driveline bind).

This site has a good graphic that explains the situation.
http://4x4abc.com/4WD101/def_turn.html

The binding feeling is a buildup of energy as a result of the torsional deflection of all the driveline parts. All the parts (including the tires) have a rotational spring coefficient and they will deflect to a certain extent until the energy built up is applying enough force to the driveline to overcome the coefficient of friction between the tires and the driving surface. At that point the coefficient of friction drops to near zero and the wheel skids and may turn slightly backward to relieve the tension in the driveline. On a low traction surface then the binding is almost undetectable because there is a very low coefficient of friction at the tires.

Read the manual. It says very specifically that 4wd is intended for low-traction situations and should not be engaged on dry pavement.

If you have "hubs" that can be locked and unlocked, leaving them locked does not necessarily mean you're in 4wd. It just means the front axle is turning. A select-able hub setup is exactly the same thing as the axle disconnect device (ADD) that is stock on Tacomas. The transfer case determines when the front and rear are locked together.

Now you're just contradicting yourself. You just agreed with the guy that says don't use 4wd on high traction surfaces.

 

I'm a liar.

 

Some spellbinding info in here

 

There is a mod for 2 low. It does not seem hard. I have been wanting it for a long time. Just have not done it. It disables the ADD. Do a search and it will come up. I think to title is 2 low mod.

 

Yes. Your right about the 4runner. That's why input in there the context that the v8 4runners use a center diff lock in the t case. It is not the same as the part time t case found in the Tacomas. And yes the manual does say that 4lo is I tended for lo traction areas. However, he was having binding issues in 4hi from what I understood and turning at just 15 degrees. He shouldn't have that on or off road.

I respect your experience however Toyota wouldn't put out a product that will allow you to shift on the fly into 4wd if your going to have binding issues while turning into the grocery store. Most of these trucks will never see the dirt but I can assure you that there have been plenty of them who have been cruising along and wondered what that nifty switch does and turned it while cruise down the blvd allowing 4wd hi on dry pavement.



I hate the iPhone auto spell check.

 

4Lo and 4Hi are exact the same with the exception of the gear reduction. The wheels will scrub in 4Hi even at some angle less than against the steering lock. I will take a video of my own vehicle this afternoon after work to prove my point.

 

Ok. That's fair enough.

 

In a part time 4wd system when your engaged the prop shafts spin at the same rate. Going in a straight line is fine. When you turn, the front wheels and rear wheels are not talking the same path thus the prop shafts would need to turn at differing rates.

This is what cause the binding issue with part time 4wd on dry pavement

It cannot be made up with the open riffs so my ore kudos statement is not correct.

I'm going to take a video using my tru k as a test bed to see this for myself.

I've never had issue with it with my truck in the past but do not re omens driving in 4wd on dry pavement.

 

Nailed it! Technically the binding issue is still there even in low traction situations. The difference is that the coefficient of friction between the tires and the driving surface is so low that there is very little energy stored in the driveline before the tire's traction is overcome and it skids slightly.

It is this exact reason why part-time four-wheel-drive (like Tacomas) can actually handle very poorly on snow-packed and icy roads. The front and rear drivelines are spinning at the same speed which means the truck really wants to continue traveling in a straight line. That straight line might not be the direction you are trying to steer. The issue is compounded even farther if you lock the rear differential.