how fast in 4 hi

As long as you are on a surface without the traction of a clean dry asphalt road there is no reason you couldn't go as fast as the Jeep will take you. Whether you want to drive that fast on a surface with limited traction however is for you to decide.
 
swany said:
ok i am new to 4x4 diving and was wondering what is the fastest you can drive in 4hi say on a snowy road or something?
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what transfercase do u have? Whenever u post try to give as much info u can, such as year, motor, tranny, transfer case.

Since diff tcases work diff, we need and like info.
 
I have the NP242 transfer case (with full-time 4x4). Since it's a full time unit, I could run it in four-wheel full time 24-7, even at highway speeds, without a problem. The 231 should be the same, as long as you're not running on dry pavement-type surfaces.
 
Im kinda woundering about this, and have a NP-242. But when you engage Full Time that makes the transfer case like a LSD? Only has power goto the front when it slips? Then Part Time the transfer case has power to the front all the time? And the rest I already know...
 
i have a 94 with a manual trans and 4.0 the transfer case is stock whatever came in those. i was just thinking like if there was a foot of snow on the road which is not uncommon around here is i can drive home from work in 4 hi at like 35-45mph?
 
The NP 242 has an open differential between the axles in full time mode. When you go around a curve and the front tires start to fight back because the rear axle is rotating faster, it cuts power to the front axle just as a regular in-axle differential cuts power to the inside wheel when the outside wheel overdrives it. Of course this also means that under certain conditions, with an open diff in the transfer case and open diffs in both axles, you could end up with 1-wheel drive, just as you would with a two-wheel drive vehicle when it spins a wheel on ice. Hence the option of putting it in part-time to get both axles locked together. You're then guaranteed at least two driven wheels at all times.

In theory you can go as fast as you want in part-time 4WD, but of course if conditions are such that you need it then it's not wise to go very fast. On snowy highways with good tires, I find 40 pretty comfortable, 45 ok on occasion, but any more is asking for trouble.
 
I don't think the transfer case for a 242 is a "limited slip"...is like an open differential. I know if I punch it when it's snowy...it's possible for only one wheel to spin (a limited slip wouldn't act like that).

The center differential (transfer case) of the 242 is what allows it to function as a full-time four-wheel drive. More modern systems, or different systems (quadra-trac and quadra-drive) utilize more intelligent systems to send torque to wheels with traction (wheels not spinning), but older systems (like the 242) simply employ an open diff in the transfer case to provide safe, non-damaging, full-time four-wheel drive.
 
I believe it says in the owner's manual and on Jeep's website no faster than 55mph in part time and 25mph in 4-lo. If you're wanting to go 55 and be in part time chances are, given the conditions, you shouldn't be going that fast anyways.
 
Well I think I was correct. The transfer case does nothing to the wheels, just sends power to the front or rear.

Yes limited slip might have been the wrong term, maybe locker since thats what Part Time does. But just think of the front axle as the left wheel, and the rear axle as the right wheel, then the transfer case is your differential. FullTime you get power, but loose it when you slip. Then Part Time you need to be on a loose surface for the wheels to slip because the power has to leave somehow, but youll always have power going to the front and rear. Thats why you get that jerk when turning in Part Time.
 
Slo-Sho said:
I've gone as fast as 70 mph on snow covered highways in Part time. I have also driven at a sustained 40 mph in 4LO.
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and this post shows that you need to remember something.
4WD get's you going faster, and may even aid in directional control, but it doesn't make you stop any faster than any other vehicle on the road.
 
I've driven many times at highway speeds in Full Time. Especially if it rainy. My XJ feels much more stable in Full Time. I mainly use 2wd in the summer for better gas mileage but as soon as the wheather starts getting iffy and the temp starts going below freezing at night, I use full time in case I hit a slippery patch. In New England that's about November thru March.

I'll second the comment about braking. Too many people think 4wd is a license to speed in bad wheather.
 
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XJoshua said:
Well I think I was correct. The transfer case does nothing to the wheels, just sends power to the front or rear.

Yes limited slip might have been the wrong term, maybe locker since thats what Part Time does. But just think of the front axle as the left wheel, and the rear axle as the right wheel, then the transfer case is your differential. FullTime you get power, but loose it when you slip. Then Part Time you need to be on a loose surface for the wheels to slip because the power has to leave somehow, but youll always have power going to the front and rear. Thats why you get that jerk when turning in Part Time.
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I keep hearing that in Full Time you don't get the same traction. True up to a point. I used to have an '87 with Full Time, went hunting to all kinds of terrain only once when I got stuck in deep mud I had to go in to Part Time.
I now drive a '96 with FT TC, keep it in FT all the time and never experience any wheel slip at any time. I think the 231 TC is great if you live in the boondocks and use the XJ only on unpaved roads or four wheeling only.
I think Chrysler made the 242 available on the better XJs and ZJs to force the customers to pay the higher price. Too many people got stuck with the inferior 231 and Part Time system either because they didn't know better or couldn't afford better.
You get your moneys worth with the FT system, you have the best of both worlds.
 
I love the 242, I rarely used the part time 4wd. Whether its actually better depends on what you are doing with it, generally the 231 is better when it comes to off-road modified vehicles. You can run in part time at any speed especially if its in a straight line.
 
falcon556 said:
I keep hearing that in Full Time you don't get the same traction. True up to a point. I used to have an '87 with Full Time, went hunting to all kinds of terrain only once when I got stuck in deep mud I had to go in to Part Time.
I now drive a '96 with FT TC, keep it in FT all the time and never experience any wheel slip at any time. I think the 231 TC is great if you live in the boondocks and use the XJ only on unpaved roads or four wheeling only.
I think Chrysler made the 242 available on the better XJs and ZJs to force the customers to pay the higher price. Too many people got stuck with the inferior 231 and Part Time system either because they didn't know better or couldn't afford better.
You get your moneys worth with the FT system, you have the best of both worlds.
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X2, ya i have a 242, and only once i have put in PT, mind u i dont rock crawl, but for everyday snow mud ice and etc, the FT is great, no bind up or problems, eventhought i want to put a limited slip in the front, have on in the back.
 
bjlinma said:
My XJ feels much more stable in Full Time. I mainly use 2wd in the summer for better gas mileage but as soon as the wheather starts getting iffy and the temp starts going below freezing at night, I use full time in case I hit a slippery patch.
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Unless you can disconnect the axles and driveshafts I don't see how the mileage would change.
My 01 WJ has a little gismo that gives you instant gas mileage.
I tried it with the 242 in 2WD and 4WD on the same road and couldn't tell.
All the parts turn regardless of mode. I told my wife that drives it that the full time is the norm and she should never change it from there.
She loves it. She can even turn the radio on from the steering wheel, go figure. She is not capable of appreciating the beauty of my XJ.
 
falcon556 said:
Unless you can disconnect the axles and driveshafts I don't see how the mileage would change.
My 01 WJ has a little gismo that gives you instant gas mileage.
I tried it with the 242 in 2WD and 4WD on the same road and couldn't tell.
All the parts turn regardless of mode. I told my wife that drives it that the full time is the norm and she should never change it from there.
She loves it. She can even turn the radio on from the steering wheel, go figure. She is not capable of appreciating the beauty of my XJ.
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them little gizmos that are factory MPG meter, are not really accurate.
now try one fuel tank on 4X4 FT and one tank on 2X4, u will see a diff.
rocketwhore.gif
 
jeepdude10000 said:
one fuel tank on 4X4 FT and one tank on 2X4, u will see a diff.
rocketwhore.gif
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I cannot do that. Too many variables in driving style, speed, temperature, terrain etc. for me to tell.
I'll take your word, how many mpg does it cost me to be in FT 4x4?
 
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