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Another NP242 question

R

Rob D

NAXJA Forum User
NAXJA Member
Location
Pittsburg CA
I know that with the NP242 that when full-time is selected that the front/rear outputs are not locked. But I noticed that when I had my front drive shaft removed that having the full-time selected was about as useful as being in neutral. Is this normal or an indication that it's just worn out? I thought there would be some power going to the rear with some slippage, sorta like a limited slip rearend, not like an open differential where all power is applied to the path of least resistance. I'm getting ready to do a rebuild on this thing anyway so I figured I'd ask before I tear it down so I can get the parts needed before I start. Thanks in advance for any help.
 
To me that doesn't make any sence, in my Jeep full time is a solid lock front to back and part time is for driving on the road. maybe mine is weird I don't know. I wouldn't think it should spin freely when in 4wheel drive though but I also don't know how the power is split in the 242.
 
Actually, that seems normal to me.

The 'full-time' option in the NP 242 is exactly like an open diff. It allows slippage between front & rear so it doesn't bind and break. I know the 249 does this through a viscous coupling, but the 242 does it mechanically. I don't think you have a problem Rob D, but I'm not an authority.

If it did this in 'part-time' then I'd think you had a problem.

:)
 
Sounds about normal....full time on the 242 does split the power with viscous coupler, but when you don't have a front shaft on, it's way to easy for it to send power to the front. I don't remember what the differentation is off hand.....


Course I could be completely wrong too....haha
 
XJPhoenix said:
Actually, that seems normal to me.

The 'full-time' option in the NP 242 is exactly like an open diff. It allows slippage between front & rear so it doesn't bind and break. I know the 249 does this through a viscous coupling, but the 242 does it mechanically. I don't think you have a problem Rob D, but I'm not an authority.

If it did this in 'part-time' then I'd think you had a problem.

:)
Click to expand...


Ohhh...I didn't know it was mechanical!
 
Thanks for the replys. I guess I can get away with just replacing bearings, seals, shift fork pads and drive chain then. Thanks again.
 
dadilius said:
Sounds about normal....full time on the 242 does split the power with viscous coupler, but when you don't have a front shaft on, it's way to easy for it to send power to the front. I don't remember what the differentation is off hand.....


Course I could be completely wrong too....haha
Click to expand...
What!? There is no viscous coupler. Without a front driveshaft, how is any "power" going to get to the front axle?

EDIT:Sorry, in my incredulity I didn't see that someone else pointed this out. Also, everything sounds normal to me regarding the original post. Since there's no driveshaft, there will be no "drag" or even the slight normal resistance from the front.
 
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Timber said:
What!? There is no viscous coupler. Without a front driveshaft, how is any "power" going to get to the front axle?
Click to expand...

dadilius said:
Ohhh...I didn't know it was mechanical!
Click to expand...

Already saw my mistake on the coupler. And I meant sending power to the front output, not the axle itself :kissyou:
 
Slo-Sho said:
There is NO viscous coupler. On snow or ice while reversing, the 242 FT is useless and PT becomes neccesary if you are stuck.
Click to expand...


Why do you say it's useless? I've never had a problem with mine in the snow, even in reverse and 2 feet of white stuff on the ground. :confused:
 
I know this has been answered but heres the easiest way to remember.

2WD - Means you arent going to move in the snow
Full-Time 4x4 - Means you can drive on the road full time in that setting.
Part-Time 4x4 - Means you can drive on the road part time in that setting.
4Lo - Means your having some fun
 
dadilius said:
Why do you say it's useless? I've never had a problem with mine in the snow, even in reverse and 2 feet of white stuff on the ground. :confused:
Click to expand...

I say the Fulltime option on the 242 is useless on slippery surfaces IN REVERSE because it will send 100% of the power to the rear axle if you hit the gas more than 25% or trying to ascend an upward driveway backing up. It can also send 100% power to the front inside tire (going forward) with the wheel turned either way if your motor makes enough torque, I can do this on my rig w/ 31's on wet pavement.

In 2 feet of "white stuff" I stick with the good 'ole 4 part time, full time is used for rain and semi-covered slick roads where driveline bindage could be a problem.
 
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On my 98 limited with the 242, On my steep drive covered with ice in reverse 2wd would not get me off the street, however shifting into full time took me right up it in reverse no problem. And I am not light on the right foot. To me it is far from useless in ice and snow regardless of direction.
Just my pennys worth, it used to be two cents but then I got audited.
 
Slo-Sho said:
I say the Fulltime option on the 242 is useless on slippery surfaces IN REVERSE because it will send 100% of the power to the rear axle if you hit the gas more than 25% or trying to ascend an upward driveway backing up. It can also send 100% power to the front inside tire (going forward) with the wheel turned either way if your motor makes enough torque, I can do this on my rig w/ 31's on wet pavement.
Click to expand...
...is absolute conjecture

Summary:
Break Traction
 
kubtastic said:
...is absolute conjecture

Summary:
Break Traction
Click to expand...

I speak from experience driving in CNY winters. If anybody thinks that with the 242 TC in Full time mode both axles will always recieve power, they're dreaming. :gee:


Oh, and before you call bullshit on someones post, why don't you try knowing what you're talking about.
 
Slo-Sho said:
Fulltime option on the 242 is useless on slippery surfaces IN REVERSE because it will send 100% of the power to the rear axle if you hit the gas more than 25% or trying to ascend an upward driveway backing up. It can also send 100% power to the front inside tire (going forward) with the wheel turned either way if your motor makes enough torque
Click to expand...
SPOBI--put up or shut up.
 
Nice answer.
Edit: Why don't you just get (and look at) some files online (PDFs, usually) of the different t-cases and compare what the specs are? Granted, specs don't always translate into real-world performance, but I've had results directly opposite of those you're claiming--for years.
 
throttle at 25% should tip everyone off that the numbers are essentially fabricated. Made-Up. Try 27% throttle. That's the conjecture.

....define slippery. Is there a coefficient of friction you'd like to supply or is it just "CNY slippery"
 
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