Is this normal....

Nice little forum you have here!
Smart guys, too.

About not engaging part time 4WD (that's what you have and its called "part time" because it can only be used part of the time = off-road) on high traction dry surfaces - if you do, sooner r later something on your truck will break.

To engage 4WD to keep things lubricated is dinosaur advice (I know its in the manual, but its still a century behind). All moving parts related to 4WD are moving in oil or grease while in 2WD - no need to "lubricate" occasionally. You should concentrate on lubricating other things.
However, one thing that needs to be operated/moved every once in a while is the automatic front axle disconnect. I would hit the 4WD button a few times for a minute or so while driving at moderate speeds (at higher speeds the binding effect might take place and the system won't release 4WD - it will stay engaged and could cause damage).

OK nuff said - I'll go back to the beach.

 

Chris,

glad to hear that you have made that point before.

 

Not sure about the Tacoma, as I didn't read the OM, but the OM for the FJ says to drive in 4x4 for about 10 miles per month. If you don't live in an area where 4x4 driving is plentiful, and you want to keep things lubed, you don't have much choice.

Personally, I think the ' 70 mph ' has more to do with his cracked case than merely driving on pavement in 4x4. Unless you're AWD, you should never drive 70 mph in 4x4. An accident with detrimental consequences.

 

70 mph in pt 4WD on dirt should be just fine - how would Baja racers ever get to the finish line if they could not step on it.

http://4x4abc.com/4WD101/how-fast-4WD-AWD.html

 

Actually, A few weeks ago I was towing a rather heavy (1 ton?) scissor lift up a paved incline in town. Naturally, the light changed to red, and I had to stop. Tried to get going again, but my taco wouldn't pull the hill in 2WD first with a load like that. Not wanting to smoke the clutch, I used the granny side of 4WD to pull the hill until I could get back into 2WD.

Not sure if that was good for it, but it lived.. And I didn't smoke my clutch.

 

You did absolutely the right thing. A short distance at moderate speeds will stress but not kill the 4WD components.

Of course full time 4WD with an open diff in 4Lo would be perfect for towing. Actually all pickups should have full time 4WD, because they are the ones most likely to pull heavy loads - especially for maneuvering heavy trailers in tight (paved) spots full time 4WD low is perfect. Steep hills on pavement as well.
Also, by using (full time) 4WD for towing the torque load for each axle is half of what it would be for the rear alone. Less wear and tear. And as mentioned before you will have the benefit of functioning ABS. Very valuable with a heavy trailer load.

One more thing, stability control makes towing so much easier. All negative effects a trailer can have on the tow vehicle are eliminated. Saved my ass a couple of times already. From experience you feel the jack knifing coming and stability control steps in and saves you. Very impressive. But it would be best with ft 4WD.
http://www.4x4abc.com/stability-control/esc-easy.html

So, why are manufacturers still selling us dinosaur technology (part time 4WD) on supposedly modern trucks?

 

Exactly my point, 4lo gives you much better control - however, in part time you are creating tons of stress (especially when the steering gets involved).
In full time 4WD low range you would not put that stress on the drive train.
Stress will make parts fail sooner than they should.

Part time 4WD combined with 4 wheel steering would do all right as well (Chevy had that briefly on some pickups).

 

The link in post 9 here is interesting.

But I wonder if it isn't even a little worse than that. I have a pre-runner, but my tractor is 4WD.

On tractors the front gear ratio is a intentionally little shorter (4-5%) than the rear. The theory is the ratios can't be made EXACTLY the same, so they intentionally bias the gearing to keep the front wheels pulling when the drivetrain inevitably winds-up. Otherwise, the front tends to bind and make steering really treacherous.

I wonder if they do the same thing on trucks. Seems like they would have to. The basic drivetrain components are the same (even the diff lock) and the potential speed of a truck would make this MUCH more of a problem. My tractor is good for 12 mph

 

reminds me of marge simpson in her canyonarro lol
​

 

4 wheel steering has been around for about 100 years to make 4WD more useful - and you are right, it is too complex to become standard.
http://www.4x4abc.com/G-Class/g5.html

Full time 4WD with lockable center diff is the more workable solution. Two axle diff locks on top of that are ideal.

 

Your front tires on your tractor are probably much smaller then the rear? On pickups front and rear tires should be relatively the same height, making it much easier to match up gear ratios. The binding effect is mostly caused from turning, even slightly. Also your tractor is designed to work with some wheel spin, keeping the front biased would only help the situation. Plus the size and strength of components is like night and day!

 

Yeah, wheel size is accounted for (it's an important consideration when mounting tires, that's the only reason I know about it) and yeah, there has to be some relative slip. My point was it is done intentionally. Here's a blurb:

Proper tire sizing/matching on front wheel assist tractors is a function of insuring that the front axle 'lead" specification is kept within acceptable design and operational limits. Front axle lead (or slippage) is necessary on front wheel assist tractors in order to realize the benefits of front axle tractive assistance. Desired front axle lead is expressed as a positve increase in front axle speed over that of the rear axle, usually in terms of percentage (ideally +1%-+5% for most front wheel assist tractors). Lead percentages outside of this range will lead to problems such as accelerated tire wear, difficult steering, loss of tractive assistance from the front axle as well as increased drive train wear with premature failures. Negative lead (or slippage) will, from the outset, totally negate any potential advantages offered by front wheel assist.


No final gear ratios will ever be *exactly* the same. Without some slip somewhere, even little bitty teeny tiny differences in pitch diameters and rolling diameters will accumulate into windup, esp. if you are going street speeds. Hence that jeep transfer case exploding at 70mph.

No argument tractors are much tougher and much slower, which makes all this LESS critical than for a truck.

I figured one of you 4x4 guys would know all about it.

 

can't know it all - not enough time - beers at the beach have high priority