NP 231 to NP242, feasable?

[ECKSJAY]

Doesnt really matter what the NP242 does fact is he said he did a tcase swap and one of the reasons was because he couldnt use lockers... the NP242 Does have part time.

But you KNOW why he said that. Fulltime won't operate as intended...and he didn't want to keep the 242 strictly because of that. Stop being silly. ig:

 

[AIbandit]

he didn't want to keep the 242 strictly because of that.

So that justifies a T-Case swap? He could just not use full time. It would be just like a 231 only not.

 

[fubar XJ]

I use my 242 full-time occasionally on mixed pavement, snowy, and forest-service roads, so I went with selectables. The full-time is great on mixed snow/ice and dry pavement roads too, you don't have to shift back and forth and you maintain 4-wheel pulling power when needed. Yes, you "can" run auto-lockers with a 242, but it makes the abovementioned full-time use on a mixed snow/dry road worthless, as you'll in effect be running in part-time 4-hi on the high traction dry pavement sections, and we all know that that is a no-no.

So you lose a nice function that the 242 provides by putting an auto-locker in the front. That's all he was saying.

 

[ECKSJAY]

So that justifies a T-Case swap? He could just not use full time. It would be just like a 231 only not.

Depends who ya are.

 

[muduck18]

So that justifies a T-Case swap? He could just not use full time. It would be just like a 231 only not.

Do you have a 242?
Have you ever tried to find part time when you have one tire that is ever so slightly low on air pressure?
good luck...

 

[bluedragon436]

Great writeup I found for this swap, just thought I would share it here: http://www.weatherlover1.com/jeep/242.htm

 

[sjx40250]

Interesting discussion. I don't read a logical, theoretical explaination why a front locker and the 242 in 4Hi Full doesn't work.

1. 2WD - no impact cause no connection
2. 4 Full - auto locker controls left and right, 242 open between front and back
3. 4 Part/Hi and Lo - auto locker contols left and right , 242 locks between front and back like a 231.

I can see unexpected behavior with 2 due to it being a different set up than any 231 Tcase configuration might present. Since the tcase is open, if the rears don't have traction, the front,left, right or both would not pull. At least if you have traction on the rear and one front, you would have 3 WD!

 

[muduck18]

Interesting discussion. I don't read a logical, theoretical explaination why a front locker and the 242 in 4Hi Full doesn't work.

1. 2WD - no impact cause no connection
2. 4 Full - auto locker controls left and right, 242 open between front and back
3. 4 Part/Hi and Lo - auto locker contols left and right , 242 locks between front and back like a 231.

I can see unexpected behavior with 2 due to it being a different set up than any 231 Tcase configuration might present. Since the tcase is open, if the rears don't have traction, the front,left, right or both would not pull. At least if you have traction on the rear and one front, you would have 3 WD!

First off it does "work"
But (as explained a couple months ago) full-time becomes a useless tool for on road driving.

Do you understand how an auto locker works?
Have you ever driven a locked 4x4 on pavement?

Here is the theoretical explanation...

When you are driving and on the accelerator the drive from the drive shaft engage the "lock mode" which is just to say that independent movement of the tires is only allowed when the drive shaft is not powering the axle.

When you have an auto locker in the front and rear and you engage full time 4wd you are essentially saying "2 wheels in front OR 2 wheels in back MUST DRIVE" while this is all fine and good, until your vehicle needs to turn.

if the front is under load the wheels will buck and chirp and feed back your steering wheel.
If the rear is under load the rear will lock and cause both rear wheels to push the front at the same rate.
When this happens your ability to turn in full time is basically the same as when you are in part time so that portion of the T-case becomes useless.

The worse part about that situation is that with full time 4wd you will not be able to predict when the transfer case will decide to put power to the front or rear since it will choose which to send power to based on the path of least resistance.

Imagine dropping your jeep into 4wd midway through a turn.

 

[winkosmosis]

First off it does "work"
But (as explained a couple months ago) full-time becomes a useless tool for on road driving.

Do you understand how an auto locker works?
Have you ever driven a locked 4x4 on pavement?

Here is the theoretical explanation...

When you are driving and on the accelerator the drive from the drive shaft engage the "lock mode" which is just to say that independent movement of the tires is only allowed when the drive shaft is not powering the axle.

When you have an auto locker in the front and rear and you engage full time 4wd you are essentially saying "2 wheels in front OR 2 wheels in back MUST DRIVE" while this is all fine and good, until your vehicle needs to turn.

if the front is under load the wheels will buck and chirp and feed back your steering wheel.
If the rear is under load the rear will lock and cause both rear wheels to push the front at the same rate.
When this happens your ability to turn in full time is basically the same as when you are in part time so that portion of the T-case becomes useless.

The worse part about that situation is that with full time 4wd you will not be able to predict when the transfer case will decide to put power to the front or rear since it will choose which to send power to based on the path of least resistance.

Imagine dropping your jeep into 4wd midway through a turn.

In full time, the front and rear are both always powered. It doesn't choose to send power either direction. So on every corner the front will lock unless you let off the gas.

 

[ehall]

no, full-time uses an open differential to shift power between the driveshafts the same way that an open differential in an axle transfers powers between the wheels. moreover the 242 differential has a bias towards the rear, so when you are driving straight the rear is powered and then when you go into a turn and the front outside wheel gets the biggest arc power shifts to the front

in part-time the front and rear driveshafts are fully powered

the problem with autolockers is that the sudden shift in torque to the front can be interpreted wrongly, causing it to engage right when you don't want it to

 

[RCP Phx]

Lets clarify this a little,they are actually "auto-matic un-lockers",they are always locked(when in 4wd) until the tires see a difference in speed!

 

[winkosmosis]

no, full-time uses an open differential to shift power between the driveshafts the same way that an open differential in an axle transfers powers between the wheels. moreover the 242 differential has a bias towards the rear, so when you are driving straight the rear is powered and then when you go into a turn and the front outside wheel gets the biggest arc power shifts to the front

in part-time the front and rear driveshafts are fully powered

the problem with autolockers is that the sudden shift in torque to the front can be interpreted wrongly, causing it to engage right when you don't want it to

The rear bias is like 52% - 48%. The front wheels are always getting torque, the center diff has no choice. Just like both rear wheels are getting power in RWD mode. It's an old myth that an open diff is "one wheel drive".

 

[muduck18]

The rear bias is like 52% - 48%. The front wheels are always getting torque, the center diff has no choice. Just like both rear wheels are getting power in RWD mode. It's an old myth that an open diff is "one wheel drive".

Really?

A Myth?

You can't be serious.

Its path of least resistance, so as long as you are on pavement you have grip, but you are still one wheel drive if you have one wheel slipping.

 

[muduck18]

Lets clarify this a little,they are actually "auto-matic un-lockers",they are always locked(when in 4wd) until the tires see a difference in speed!

I don't know if I agree with that statement.

They are automatically locked when there is power to the Drive shaft.
But ONLY when there is no power to the drive shaft they allow for wheel slip.

 

[winkosmosis]

Really?

A Myth?

You can't be serious.

Its path of least resistance, so as long as you are on pavement you have grip, but you are still one wheel drive if you have one wheel slipping.

That's not the same as 1 wheel drive. That's just differential action. On pavement, with traction, both wheels are powered. Although when you go around a corner, since the diff sends both wheels equal torque, the one on the outside gets more power because power is a factor of rpm and torque. But it's not 1 wheel drive.

If an open diff is 1 wheel drive, the same would be true for full time 4wd, and there would never be any point in using it. But it exists for a reason... Because torque is split among all 4 wheels, reducing the chance of breaking loose on ice and on the trail.

 

[muduck18]

That's not the same as 1 wheel drive. That's just differential action. On pavement, with traction, both wheels are powered. Although when you go around a corner, since the diff sends both wheels equal torque, the one on the outside gets more power because power is a factor of rpm and torque. But it's not 1 wheel drive.

If an open diff is 1 wheel drive, the same would be true for full time 4wd, and there would never be any point in using it. But it exists for a reason... Because torque is split among all 4 wheels, reducing the chance of breaking loose on ice and on the trail.

If you drive up to a tree and hit the gas. How many wheels spin?

 

[winkosmosis]

If you drive up to a tree and hit the gas. How many wheels spin?

Put the Jeep on a lift and floor it. How many wheels spin?

When you rotate your tires, are the rears both worn evenly? Or is one more worn?

 

[RCP Phx]

I don't know if I agree with that statement.

They are automatically locked when there is power to the Drive shaft.
But ONLY when there is no power to the drive shaft they allow for wheel slip.

Thats not correct,they un-lock the one side that is turning faster.

 

[winkosmosis]

Thats not correct,they un-lock the one side that is turning faster.

So it's like a ratcheting? So what's the problem with having it in front?

 

[muduck18]

Put the Jeep on a lift and floor it. How many wheels spin?

When you rotate your tires, are the rears both worn evenly? Or is one more worn?

So your point is that when they have even resistance you get even power distribution.. I get it. I know how a differential works.

But when push comes to shove only one wheel can take all of the power from the rest of the wheels in full time and in 2wd.

In part time one wheel in the front and one in the back (based on open diff's)

The force to the other wheel is only equal to the resistance of the slipping wheel divided by the number of differentiated wheels.

No the right one always is worn more.

Thats not correct,they un-lock the one side that is turning faster.

I am not trying to argue with you This is just how I understand these to work.
When you apply force to the drive shaft it will not allow one wheel to spin slower than the other, but it will how ever allow one to spin faster? If you can explain to me how that works exactly I would love to see it proved.

The "Aussie Locker" mechanism allows a wheel to turn faster than the speed of the differential that is driving it (differentiation), but never allows a wheel to turn slower than the speed the differential and engine is turning it (traction). Therefore, a wheel cannot ever stop turning if the engine is driving it, but in a corner it can be forced to actually turn faster. Unlike a standard differential, the engine can never drive one wheel faster than the other.

You are right in theory, when the Tire initiates a faster speed than the other tire it will unlock.
BUT if you are under HEAVY acceleration THE DIFFERENTIAL IS LOCKED AND IT WILL REMAIN LOCKED.

more from their site...

Unlike some other types of lockers, the "Aussie Locker" has a locking and unlocking principal that is dynamic. Dynamic in that the more power that is applied, the harder it locks so it doesn't need large bias forces operating on it to keep it locked. The bias spring forces are minuscule and can easily be compressed with two fingers. This results in a locker that is able to lock and unlock easily even when driving on extremely slippery surfaces like mud and wet grass. The locking mechanism is so sensitive that a wheel can be disengaged with one finger when a wheel is jacked up, off the ground. The "Aussie Locker" engineering philosophy is based on two sets of opposing forces but simplified over other automatic locker designs. Basically there are two forces acting on the two gear sets.

again, as long as you are creating the force with the tire it will unlock. but if the engine has a significant amount of pressure on the drive shaft It will lock the tires.

What I am saying is that if the driveshaft has greater force, then the force attempting to turn the outside wheel faster the diff will not unlock it will make the inside wheel catch up to the speed of the out side wheel because it will not allow one tire to spin slower than the differential and 1 axle that gives you a lock condition and will push your truck just like a regular locker will push.
The differences is that it won't drag the outside tire on slow speed, no acceleration turns.

So it's like a ratcheting? So what's the problem with having it in front?

its unpredictable.

We "Do Not" recommend the installation of a locker in the front of a vehicle that will be driven on icy highways in 4WD without manual hubs. Driving on any slick surface requires additional attention to handling so test your Aussie Locker equipped vehicle in open areas under adverse weather conditions before driving on roads

I am quite sure that we have dropped way off topic on this OLD thread.
I would love to continue this conversation, either of you guys want to just make another thread and Pm me the link, feel free.