Functionality question with examples

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BillyBones

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Hello everyone,

I've been reviewing some items on the forum in regards to 4Hi(part time). I understand the logic behind it, but I what I am confused about is when it's appropriate. I've read a few examples on the board, but sometimes they conflict. So to make life easier I am going to post a few examples. What I am looking for is functionality not opinion. So for example I really want to know if it's fine for the jeep to do it, even though you might think it's pointless :) (If that makes sense).

Example 1: It just finished raining and the roads are wet and there are sporadic poodles? (edit: and puddles)

Example 2: Road is completely covered with snow (No one has driven on it, you are about to).

Example 3: Road is completely covered with snow, however countless vehicles have driven on it, compacting the snow, but snow is there, no clear asphalt?

Example 4: Roads are covered with wet/slushy snow, it's raining lightly with light wind, temperatures are below freezing?

Example 5: You are driving up slope that goes into your above ground car parkade and the bottom half of the slope is very icy due to water flowing down and freezing, however half way up it is dry cement, can you use 4HI (Part time) for the first half and then back to 2HI for the cement.

Example 6: It's snowing heavily, but every now and there is a small area that may have dry/clear cement. Driving over the dry/clear cement will take approximately less than 5 seconds.

Lastly, does it matter how often you switch between 2HI and 4HI (Part time) during one trip, for example, maybe the first part of your trip is in a heavy covered snow area, then it turns into clear highway, then back into a heavy snow area? Sorry if this has been revisited time and time again, but I really want to know what the Jeep can do without breaking. From that I can judge based on my driving ability whether or not it should be used.

Thanks.
 
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JeepJeepster

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Dont use 4hi on any hard surface. Thats all you need to know.

So, it should be safe to use it in:

-Example 1.. But only if its covered in poodles and not puddles. haha
-Example 2
-Example 3
-Example 4 depending on how much slush there is. It should be ok to use 4hi in this situation
-Example5. You would probably have to use 4hi just to make it up it, but its not a good idea to switch back and forth from 2hi to 4hi when you will not be driving straight for a few hundred feet.

So in other words, if you cannot make it in 2wd, you should be able to use 4hi.
 

Atrus

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Hre are some big generalities:

1) If your tires can slip easy, 4HI is OK.
2) I don't like to switch in and out when under load. Might be me being ****, but I always let off the gas.

A few other items:
A) You can drive in 4wd on a 90* summer day on pavement...just don't turn the wheels at all
B) There are two kinds of 4wd in the KJ - Command Trac and Select-Trac. Command Trac has a sifter that goes 2Hi, Part Time 4Hi, N, 4 Lo. Select Trac goes 2Hi, PT 4Hi, Full Time 4 Hi, N, 4 Lo. The full time option gives you the go-ahead to drive in ANY conditions in 4wd Hi.
c) The reason you can't leave it in 4wd all the time? On a turn, the axles turn at different speeds. PT 4Hi is locked - so, if one axle is spinning faster, the slow one tries to slow it down. On the flip side, the faster axle is also trying to speed up the slow axle. It puts a lot of stress on the drivetrain when the wheels can't slip easily to relieve the tension, that's when you get "binding" or "crow hopping". 4Hi FT has another differential in the transfer case - so, it's OK to have both axles turning at different speeds.
 
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Jeepman56

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Sporatic Poodles! wrc.gif That would be a lot of points. Anyway I have Command Trac and this is how I would answer:

1) No
2) Yes
3) Yes
4) Yes
5) Yes
6) Yes only if the exposed cement was in a straight line, not a turn. (Or with poodles)

You can switch in and out as many times as you want per voyage just remember to have all 4 wheels turning at the same speed when you shift into or out of it and not above 55 mph.
 

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