Part time or full time 4x4?

[Paul-JK]

Originally Posted by rjl3175

Paul if yours is an older 200 no problem with bars, the newest ones however, not possible.

2016 model. 7 months old. Front bar, side steps & brush bars been on it for 6 months. Rear bar going on in 2 weeks (though the back end hasn't changed much for years). Couldn't say for sure that bars are available for the 2017 models but there were no changes in 2017 to the front end that I'm aware of so I don't see why not.

Sorry, getting off topic.

[G.man]

Thank you for help...

I think I am getting it... slowly.

Full time 4WD has a centre differential. This is a differential same as the front and rear differential.

It allows for front differential to spin at a different speed to the rear differential as it is not a solid bar that has simply locked out (like a locker, but in this case being transfer case - centre)

Differential locks on front and rear make the left and right wheel locked to eachother. That way if one wheel is in the air, it will still spin at the same speed as the one pushed down in the ground as they are 'locked'.

LSD's allow the one in air to spin but some power will go to the one pushing on the ground (perhaps not enough though and that is why diff locks are good)

Open differential will send all the power to the wheel in the air and the ones on ground will do nothing.

Now...

AWD mode (full time 4wd) I am under the understanding that, if for example, front right wheel is up in the air... you are pretty much stuck because all the power from rear wheels will go to the front wheel in the air as well making you jammed period?

This is why 4x4 is good because at least if the front right wheel is in the air, the back wheels (if planted) will still have power and ability to push you (sort of rear wheel drive in this instance as the front differential is spinning the wheel in air only, so you only got 2 rear wheels to push you out)

If so far so good...

Then what is problem with 4Hi on the road?

The centre differential locks, making equal torque front and back... (again like the last example front right wheel in air, you still have power in your rear wheels to get you out, aka 4x4 not AWD)...

But from side to side the wheels will still spin differently no?

Or is the problem because on the street all wheels 'will' have grip, and thus none of them 'will' spin at a different rate and because of that... when you 'need them to' the locked centre wont let them spin differently (around a corner)... only because it is not designed to 'make you slip' that is a result of the ice/sand etc... but once on concrete... there is no slip and then it is 50-50 period (unless the ground moves under it) in which case then things change and thats why 4Hi can be used offroad because the ground slips so to speak creating that slippage...

So the 50-50 front and rear is fixed... but... if tires are spinning due to loose ground... it wont be 50-50 left to right... only on actual concrete will it be '50-50' and thats when it is not good...

Hope i made sense.

With all the after market support available for the JK wrangler... that uis why i wanted a JK. I can get diff locks, I can get Limited slip differentials for them etc etc... No?

Are full time 4x4 systems available for these?

[Paul-JK]

Originally Posted by G.man

Or is the problem because on the street all wheels 'will' have grip, and thus none of them 'will' spin at a different rate and because of that... when you 'need them to' the locked centre wont let them spin differently (around a corner)... only because it is not designed to 'make you slip' that is a result of the ice/sand etc... but once on concrete... there is no slip and then it is 50-50 period (unless the ground moves under it) in which case then things change and thats why 4Hi can be used offroad because the ground slips so to speak creating that slippage...

So the 50-50 front and rear is fixed... but... if tires are spinning due to loose ground... it wont be 50-50 left to right... only on actual concrete will it be '50-50' and thats when it is not good...

Correct. All 4 wheels would need to turn at different rates as you go around a corner. Front and rear diff's allow the 2 wheels on the same axel to turn at different rates but the transfer case will not allow the front & rear drive shafts to to turn at different rates. Either the wheels need to slip to allow this (by putting 2 wheels off the tarmac) or you'd risk damaging the transfer case.

You can certainly buy diff locks. Not sure if you can buy LSD for the JK but you wouldn't really need to as it already has braked traction control system fitted that basically does the same thing. If you were going to go to the expense of opening the diffs to fit an LSD you might as well just put a locker in instead.

As far as I'm aware you can not buy full time 4WD kits for them. This would usually be something that would need to be designed into the vehicle by the manufacturer and isn't something the aftermarket would usually do.

[Fruju]

The major difference between a full and part time 4wd system is the centre diff/transfer case.
In a part time JK system, there is no centre differential therefore the transfer case operates locked when 4wd is engaged, so there is a 50-50 transfer of torque to the front and rear in 4Hi and 4Lo. A full time 4wd system has a centre differential which can run 4Hi open, 4Lo open and 4Lo locked. The only time the drive out of these systems would be the same, would be if front and rear diff locks were engaged in 4Lo(4Lo locked for full time).
4Hi on road is not an issue just as long as you have an open centre differential.

[Nanook]

Originally Posted by G.man

With all the after market support available for the JK wrangler... that uis why i wanted a JK. I can get diff locks, I can get Limited slip differentials for them etc etc... No?

Are full time 4x4 systems available for these?

The aftermarket support is probably second to none in the 4x4 world. You can just about buy anything you can think of. The beauty with the Wrangler is it pretty much everything is bolt on. There isn't a great deal that requires major work to fit.

The one downfall with the Jeep is that in more remote areas of Australia there isn't a great deal of mechanical support if something goes wrong as they aren't as popular as Toyotas and Nissans. That's not to say don't take them in remote areas, some of the trips forum members have taken theirs on are fantastic.

As Paul pointed out, you don't need LSD, the traction control system the Wranglers have is a good one and more than makes up for this. It would be easier and a lot cheaper to fit lockers in than to change over the whole diff.

If you want all time 4wd then buy something that has it as you would be wasting a lot money for a vehicle that doesn't do what you want. If you are worried about safety on a wet road then buy a decent set of road tyres but then, you compromise decent traction when out in the scrub or on sand.

The Wrangler isn't the perfect vehicle, it's built to go off road first and on road second so it's road handling properties aren't up there with other 4wds. A good suspension set up will go a long way to fixing this but it will always be a compromise.

I drive a Toyota Hilux dual cab as a work vehicle with road tyres. I can honestly say, I'd rather drive my lifted Wrangler with muddies on a wet road than it.

[G.man]

Hey and thanks for the help.

So full time 4wd systems don't have a 4Hi (locked) as part time 4wds do?

If that is correct... then essenetially the part time seems a tad better offroad as you can run in 4Hi locked rather than open or lo... I would assume negligible but at least on paper it seems like that.

In terms of handling I am not concerned, I mostly owned muscle cars with drum brakes.

I never try to take corners hard... its a truck (the jeep) and to me should be driven as such. Just drive normal/slow in rain and rear wheel or 4wheel shouldn't make a difference.

I wanted a capable 4wd that I can pereonalise (moving from muscle cars to 4x4s) and I love the look of wranglers. All the other 4x4s look like cars on big wheels, the wrangler looks like a trailer (just flat sheets of metal with lights stuck to them rather than integrated into the body like all other 4x4s) Trailer seems to suit the description lol. So it looks out of place on street kinda but offroad looks perfect and that is how I wanted my 4x4 to look... like a 4x4 vehicle not a car.

Just remembered.. if you have diff locks... can they be added to a limited slip? That way you got LSD for everything and still have lockers when needed... or doesn't work that way?

Thanks for everything once again.

[Steve F]

You can't have a LSD and a Locker, they won't both fit in the rear end as they occupy the same space. Don't bother with an LSD you have traction control and all the fancy electronics anyway, just go with a locker.

Cheers
Steve