Few questions about my 4WD in my 99 Limited

[spoiler900]

Hello all, Ive had my truck for 4+ years now and love it! Its a 99 Limited 4X4 with the "multimode" selector and live in southern california and do NOT off road in it, so the 4 wheel drive is not necesary. Ive used the "all wheel drive" a handful of times to keep it lubed up and during heavy rain but have some questions I have always thought about but never actually posted

1) So if I just press the button on the left of the shifter, that engages "all wheel drive" which is technically safe to use all the time and on pavement? I used it when I went to school at The University of Arizona during monsoons (heavy heavy rainfall) to get more traction on the roads. And is it rear wheel drive bias and only sends power to the front when it feels like it need it or what?

2) And if I pull back the lever to "4 high" it locks the center diff which makes my left front and left rear tires spin together (same with right front and right rear)? No I do not have the rear locker. And I understand I have to go into neutral at a full stop for 4 lo. But is this what "4 high does"? Also, do I have to have the button on the left clicked in like i do for "all wheel drive" or just pull it back or it doesnt matter?

3) It says in the manual card on the sun visor how to engage the systems, and to engage it under 60mph. I understand its "on the fly" and I can do it while moving and have done so usually between 5-20mph. My question is am I only allowed to engage below 60mph, like can I drive it above 60mph on the highway? This would be for using the "all wheel drive" part not cent diff locked and used for heavy rainfall, more for "fun" and "traction" and to keep the parts lubed up from use than actually needing it in all wheel drive.

 

[jacobbert9]

1) Clicking the AWD button sends equal power to all four wheels. This means if you were to get stuck, only one wheel would be spinning. That is why it is safe to use onroad, it allows each wheel to spin at a different speed so you won't bind any gears.

2) Engaging 4 High does not mean that your left side tires spin together and your right side tires spin together. It means that power will be split 50-50 between the front and rear axle. On each axle, the power will take the path of least resistance. So, for example, if your front right and left rear tires were in mud but your left front and right rear were on concrete, only the tires in mud would spin. As far as the button position, it does not change anything when the shift lever is in 4-Hi or 4-Lo.

3) I personally haven't read anywhere either in the manual or on this site that states you cannot drive in AWD/4WD above 60 mph. That being said, if I ever thought that I needed AWD to get enough traction going that fast, I'd probably just slow down. Mechanically though, I can't see why it would be harmful to go over 60 mph while in AWD.

 

[WallyWest]

1) So if I just press the button on the left of the shifter, that engages "all wheel drive" which is technically safe to use all the time and on pavement? I used it when I went to school at The University of Arizona during monsoons (heavy heavy rainfall) to get more traction on the roads. And is it rear wheel drive bias and only sends power to the front when it feels like it need it or what?

Yes, you can use it on dry pavement. Your front and rear diffs don't lock, which allows one wheel to spin faster than the other. Potentially robbing power from the wheel with traction. That's what the TRAC system tries to counter. When it senses this situation it applies brakes to the spinning wheel, effectively sending power back to the other one.

When you press the button and engage 4WD the power is split 50/50 between the front and rear axles. But it's just like the diffs, if the rear is on ice it can rob the front wheels of power. I'm not sure if the TRAC system will compensate for that situation or not, I *think* it only works on each axle individually, but I could be wrong on that.

2) And if I pull back the lever to "4 high" it locks the center diff which makes my left front and left rear tires spin together (same with right front and right rear)? No I do not have the rear locker. And I understand I have to go into neutral at a full stop for 4 lo. But is this what "4 high does"? Also, do I have to have the button on the left clicked in like i do for "all wheel drive" or just pull it back or it doesnt matter?

I believe on the shifter you have if you just pulled it into 4 HI without pressing the button that it will automatically engage 4WD and then lock the transfer case. So you could press the button first and then move the shifter or just put it into 4 HI, it amounts to the same thing.

Locking the transfer case forces a 50/50 power split between the front and rear diffs. So having the rear sitting on ice will no longer rob power from the front, or vice versa. If you engage this on dry pavement and turn the wheel you'll feel it start to bind up and possibly make the wheels hop on the pavement. That's not good for the transfer case, so only lock the transfer case when you're on very slippery surfaces that will allow the wheels to slip easily.

Shifting it into 4 Lo just gears the transfer case down. You'll probably never need to use that on the road, in any conditions. But I do think your habit of engage 4WD now and then is good, I do that too. And maybe once a month I go to a dirt and gravel lot near my house and run it through every mode.

3) It says in the manual card on the sun visor how to engage the systems, and to engage it under 60mph. I understand its "on the fly" and I can do it while moving and have done so usually between 5-20mph. My question is am I only allowed to engage below 60mph, like can I drive it above 60mph on the highway? This would be for using the "all wheel drive" part not cent diff locked and used for heavy rainfall, more for "fun" and "traction" and to keep the parts lubed up from use than actually needing it in all wheel drive.

Yeah, it says that but I've never had luck engaging it at higher speeds. I do it at a max of 20mph or so, and just take my foot off the gas and let it coast. If it doesn't engage right away turn the wheel a bit, that usually does the trick. For locking the transfer case mine (a 2002) has a button on the dash. That seems to work best while stopped with the transmission in neutral. I'll push the button and the lights just blink, sometimes it will lock eventually, but if I stop and shift to neutral it immediately locks.

In the basic 4WD (AWD) mode you can drive as fast as you would in 2WD. There's plenty of cars out there with full time AWD that go a lot faster than you'll ever see in a 4Runner.

 

[Mgyver1]

Yes, you can use it on dry pavement. Your front and rear diffs don't lock, which allows one wheel to spin faster than the other. Potentially robbing power from the wheel with traction. That's what the TRAC system tries to counter. When it senses this situation it applies brakes to the spinning wheel, effectively sending power back to the other one.

When you press the button and engage 4WD the power is split 50/50 between the front and rear axles. But it's just like the diffs, if the rear is on ice it can rob the front wheels of power. I'm not sure if the TRAC system will compensate for that situation or not, I *think* it only works on each axle individually, but I could be wrong on that.

He has a '99, no TRAC on that rig.

 

[WallyWest]

He has a '99, no TRAC on that rig.

D'oh! Right, forgot about that.

OP, ignore what I said about TRAC.

 

[Mgyver1]

D'oh! Right, forgot about that.

OP, ignore what I said about TRAC.

You 01/02 snobs, not caring about the '00 and below