Serious Question: How fast in 4 High?

They probably failed cuz it was a Ford

Check out my previous post referencing this website: http://www.dodgeram.org/tech/repair/4X4/4x4_engagment.htm

It's because the differential spins the other axle backwards. You'd have to separate it from the wheel or else it'd try to spin the wheel backwards. Therefore, there is an intermediate axle separator that disconnects the right side of the axle from the differential, letting it free wheel while in 2-wheel drive.

 

Not if it's a drive wheel. This configuration is only when the front wheels are not engaged (i.e. 2wd). Both of the rear wheels are drive wheels via the differential. The front wheels are not drive wheels when in 2wd, therefore they need to spin freely. But to get rid of the old locking hubs, the wheels need to be attached to the axle. So, the new design is to lock the driver's side wheel to the axle. When in 2wd, since the transfer case is not driving that wheel, the wheel spins the attached axle. This rotation forces the passenger side axle to spin backwards via the differential. If the passenger wheel were hard mounted to the axle, it would attempt to spin the wheel backwards, so there has to be some sort of axle separator. Therefore, in 2wd, the left wheel and axle are spinning and only half of the right axle is spinning. The other half of the right axle is attached to the right wheel and is allowed to spin freely. When you engage 4wd, you are activating both the transfer case and the axle separator. This locks the right wheel to the axle, but now the transfer case is spinning the shaft and ring gear, pushing both sides of the axles forward.

 

Having fun with this, huh Larry?

Interesting how engineers come up with simple ways to make our Toys work better, and easier... Take the A-TRAC for example... using spin sensors and the braking system, we have automatic front and rear "open to locking" differentials for awesome traction, without the headaches that traditional lockers have.

 

Yeah, that discussion sure got me thinking. Thanks for pointing me towards axle disconnects, being an engineer myself, I love to learn how others creatively solve problems and make things work better...locking hubs were a pain in the a$$. I agree with A-Trac...pretty creative to brake one wheel to distribute torque to the other!

 

I agree here almost.. my 1999 5 speed has a manual trans, transfercase, and manual hubs, I can "LOCK" the hubs in when I plan to go off road,and when I need the traction I can pull back on the 4x4 lever and BINGO I have traction. When I don't need the 4x4, I can shift into 2x4 so no load on transfer case, and unlock the hub, so I 'm not spinning thefront wheels, I have less of a load on my driveline, and I save gas/friction on my cv axles and front drive shaft because I'm all manual(that's what she said)....and for those who don't know. ...It's a stronger set up, just not as convienient for those who don't like to get their feet dirty.

 

I'll probably get flamed for this but, I've been using 4H in the rain on pavement for 20+ years in my 89 pathfinder, (which I still drive today and have had 0 problems with the 4WD system) turns and all and never had any problems, just great traction when making a turn so I dont spin and not get outta the way in an intersection. Did the same in my 94 yota pickup and both my 4WD tacomas. Use it whenever you need better traction, just be aware of the binding and flip it off when you go to park or have to make a really sharp turn...I also agree with the poster in the beginning about you being much better off hydroplaing in the rain in 4H instead of 2H...

 

I agree 100%...I have a manual trans, so I sometimes use the 4-wheel to provide some control at stop lights in the rain where paint or worn down roads make it more difficult to "launch". I'm also make sure it's off before I make any turns...even if a parking spot is snow covered, I try to turn it off before parking. Or at least once I'm in the spot, I'll back out of the spot, turn off the 4-wheel, then roll back in in 2wd to ensure any wrap is spun out and not stressing the drivetrain the entire time its parked.

 

I am the guy everyone called a moron. If my drivetrain breaks I will let everyone know. I get bind in 4H or 4L with VERY SHARP turns like in a parking lot... even on dirt/mud where I need 4H. On the street its just a self centering feel and it does not bind enough to matter. I have tried punching it on right hand corners in the rain in 2H and 4H and it just sticks every turn in 4H to the point you almost cant lose control... 2H I get it to fishtail and VSC cuts in killing my speed and I can end up a lil sideways to the point I have to stop if I push too hard. To say the front end will lock up in the rain and not allow progress becasue it does that at FULL LOCK is beyond ridiculous. It barely has some tug on more gentle turns. I mean think about it... if it would harm the drive trian to do something that requires the tires to break contact with pavement ANYTIME you applied enough power to bark your tires would be damaging your drivetrain.

Its funny you hear things like "it will break your 4WD to use 4HI on pavement" yet I have NEVER heard of anyone this has happend to. I have a friend with a spool rear on a Jeep and it barks the tires on turns and it does not break anything. I did this in an old Cherokee (4H in rain) and it never broke... heck I jumped it off a 10 foot cliff by accident once and the drivetrain held up. But a little lane changing in the rain is going to kill my Toyota 4WD parts? Gimme a break, it cant be THAT weak. People who say "you are lucky you didnt break anything" when someone drives in 4WD on pavement are just ridiculous... the parts are WAY tougher than that. When explaining the rear locker and how it works to people unfamiliar with lockers I do it on pavement and show them how the tire cant make the corner and it barks to catch up and widens turns. Not real afraid of anything breaking either.

Is it good for tight turns? No. Does it increase drivshaft CV wear... most certainly. It is not going to cause some catastrophic failure or send you jack knifed in the rain though.

 

I agree that you can push the drivetrain and it may not break, but why force the driveline through those kinds of undue strains? Changing lanes in the rain is no big deal, but taking a hard turn to the point that the tires hop and bind up is not healthy for the drivetrain nor is it safe. Like whippersnapper02's post, I too have seen failures occur. Yes, they are tough and can handle a lot, but why needlessly force premature failure????