rattlewagon

Winner winner chicken dinner!

combatcarl

Oh, btw, Chuck, that is a DANG nice Landcruiser...you selling?

Jkelley429

iTrader: (1)

technically your axle shafts arent locked together. if you unlock your hubs and put your t-case in n or 2hi and turn your front driveshaft by hand only one cv axle will turn. if they were locked together both would turn. the front diff works just like the rear.

combatcarl

K...so if your outside front, and outside rear are being driven, (which is what open/open diffs will prefer to do, your frontend traveling distance is still longer than your rear...? Meaning more driveshaft rotations at one end than the other? (in 2HI, hubs locked) In 4HI, your driveshafts locked together....its your truck, not mine. If I'm seeing this wrong, its cool, I'm far from smart.

snobdds

Like I said, I find it funny all the differing responses here. The answer has already been posted so I don't need to beat a dead horse.

Just goes to show, the more you think you know the less you actually do...

And oh...I have never quoted myself before

4Crawler

iTrader: (3)

Yep, with a part-time 4WD system, the front axle will make more rotations than the rear in a turn. If you don't believe that, hit a parking lot with a puddle in it, drive through the puddle and then crank the steering wheel all the way over and make a U-turn. Stop and hop out and look at the wet tire tracks and see which are the front and rear tires and you'll see the fronts make a wider arc than the rears.

With open diffs, both wheels on the axle will be driven (assuming adequate traction) and the diff (ring gear) will spin at the average of the inner and outer wheel speeds. since the front wheels travel farther on average than the rears, the front ring gear wants to make more rotations than the rear, thus the front drive shaft wants to turn more turns than the rear and then you hit the t-case. There the front and rear drives are tied together with gears (or a chain) and gears or chain sprockets always spin the same speed, so something has to give. Usually it is a tire slipping and if you are on gravel, dirt, snow, ice, that is not a problem. On pavement, wet or dry, it takes a lot to make the tire slip, so lots of stress builds up in all the drive train parts.

First time I made this "mistake" was that I had driven up to the mountains in the snow (in 4WD) and we pulled into a covered parking structure and didn't think to unlock the hubs or shift into 2H. I think we saw a parking spot behind us and I pulled a tight u-turn and there was a loud bang. Luckily it was only that one of the tires had gone over a fair sized pebble, and that was enough to cause that tire to spin loose and shoot that pebble off like a shot. I guess the bang was from the sudden release of built up torque in the drive train.

I have run in 4WD (or at least front hubs locked) on the highway where there is intermittent snow/ice then bare pavement. If the road is fairly straight, no problem leaving it in 4H, but if it looks like a long stretch of bare pavement or some turns coming up, I'll pop the t-case into 2H until I next see snow covered pavement coming up. Basic rule I use is that if the road is slippery enough to let the tires slip enough to prevent binding in the t-case, then it is slippery enough to need 4WD. If is is not slippery enough to prevent binding, then you don't need 4WD.

ChuckDelta

Sorry, not selling, just bought it last spring or summer, and I love it! I'm wondering if I can make it last long enough to be the last car I ever need to buy?

Thanks for all the info everyone, it's really helpful!

combatcarl

Ah well, I wouldn't sell it either. Every good one I see around here, is either beaten to poopoo, not for sale, or WAY outta my price range. Had a perma-borrowed one when I was in NY, all rusty, but a sweetheart. Ran like a top.

Jkelley429

iTrader: (1)

ok. i shouldve looked that up before posting. i was wrong with my previous posts although i do agree with 4crawler on the highway driving thing.

tj884Rdlx

this is only true if you NEVER TURN.

toyota t-case has no center diff, so when you turn, you'll have binding between the axles. that's the difference between a part-time 4WD system like we have, or full-time 4WD system which has a center differential.

this diagram shows why:


http://www.4x4abc.com/4WD101/def_turnfull.html

rattlewagon

Remember kids, ALWAYS read the entire thread before posting.

He already admitted to being misinformed.

tj884Rdlx

sorry, just found a good image i thought helped illustrate what we were all discussing. i wasn't hammering anyone.

4Crawler

iTrader: (3)

That is a very good picture and you could see the same thing with wet tire tracks in a sharp turn.

aviator

You can lock the hubs and drive around all day everywhere with no issues all you are doing is essentially what toyota did when they went to the ADD hub... this gives you shift on the fly capability... all you will do is hurt the fuel economy a bit and increase the wear on the CVs.
However you should not shift into 4wd with the hubs unlocked... if the hubs have not fully disengaged [and this can happen if the springs are weak or the grease stiff with cold/contaminants] you can damage the spider gears in the hubs or throw the truck out of control with the sudden unbalanced grip.
As previous posters have said if traction is in doubt or bad wx is forecast lock'em up other than that let them free wheel for best all around results...

Teuf

Unless you have tire spikes, Nothing works on black ice. I vote for the hubs locked 4wd when you need it.

ThatGuy1295

4WD without the hubs locked is fine. Doesn't hurt anything

aviator

I would agree generally no unless the hubs have'nt completely released as I said.

Teuf

Why run 4wd and not lock the hubs? I don't get it, you just have to get out n lock them. With manuals anyway.

ThatGuy1295

4Low without hubs is 2Lo with is cool

Teuf

Now thats cool. How low can you go.