np231 or np242 for cherokee's

[958mtm]

To anyone who has personal experience or knows a bit about this, which case is preffered. I realize there seem to be a lot more after market parts available for the 231 already. But i'm wondering about durability and streetability and what not. thanks

 

[mbryson]

I think they'll both 'hold-up' for Cherokee use. I used a 242 and I know quite a few others that have used a 231 with good reliability. I'm thinking you use what you have until it breaks, then upgrade if it didn't have a long service life.

 

[Badcop]

Im using the 231 in both my TJ and XJ, havnt had a problem yet with either, both DD's and weekend warriors.

 

[Brett]

All my Cherokee's have had the NP 242 and I've never had a problem with them.

 

[Brad]

The 242 has a fulltime 4WD option, the 231 has a slightly higher torque capacity and more aftermarket support. You'll be able to get a SYE for either so it probably boils down to what's important to you: fulltime or the options of 4:1 and 2Lo.

 

[958mtm]

The 242 has a fulltime 4WD option, the 231 has a slightly higher torque capacity and more aftermarket support. You'll be able to get a SYE for either so it probably boils down to what's important to you: fulltime or the options of 4:1 and 2Lo.

Very important question here... I have the 242 and do a lot of driving in 4 wheel while on the streets, like when it's snowy or crazy rainy. I use the full time option which is 1:1, so it drives exacty the same, my question is can you do this with the 231. I want to be able to be cruising around in 4 wheel during these wheather conditions, so is that possible, if not what are all these folks doing in the snow?

 

[Brad]

Very important question here... I have the 242 and do a lot of driving in 4 wheel while on the streets, like when it's snowy or crazy rainy. I use the full time option which is 1:1, so it drives exacty the same, my question is can you do this with the 231. I want to be able to be cruising around in 4 wheel during these wheather conditions, so is that possible, if not what are all these folks doing in the snow?

The 231 has no fulltime option. Cody summed it up like this once: if the weather or traction is so bad that you need 4WD on the road, then traction is bad enough you should be able to use 4HI with no problems. The fulltime 4WD is a nice option for inexperienced drivers, but it gives a false sense of confidence. Otherwise keep it in 2WD and go slow. I ditched my 249 when the VC failed, and frankly I've never missed the fulltime option. I drive Parleys between Park City and SLC 3-5 times a week and rarely use anything other than 2HI. In the event 4WD is needed, the 231 can be shifted 2HI -> 4HI on the fly. The aftermarket was more important to me so I went 231 instead of 242. The 231 is a smaller case and can be made to be as small as an Atlas with JB's Super Shorty kit.

 

[958mtm]

The 231 has no fulltime option. Cody summed it up like this once: if the weather or traction is so bad that you need 4WD on the road, then traction is bad enough you should be able to use 4HI with no problems. The fulltime 4WD is a nice option for inexperienced drivers, but it gives a false sense of confidence. Otherwise keep it in 2WD and go slow. I ditched my 249 when the VC failed, and frankly I've never missed the fulltime option. I drive Parleys between Park City and SLC 3-5 times a week and rarely use anything other than 2HI. In the event 4WD is needed, the 231 can be shifted 2HI -> 4HI on the fly. The aftermarket was more important to me so I went 231 instead of 242. The 231 is a smaller case and can be made to be as small as an Atlas with JB's Super Shorty kit.

What is the difference between 4hi and full time? I belive it says 4hi on my floor read shifter, but full time on my dash. So are 4hi in the 231 and full time in the 242 the same thing?

 

[Ken]

It's pretty close to the same thing. Basically full time was ment for the rain and slick road conditions. I have a 242, but would rather have a 231 due to the availability of parts. They're a lot more common. Now a HD 242 would be the way to go out of a dodge truck. I think dakota? I could be mistaken though.

 

[Brad]

What is the difference between 4hi and full time? I belive it says 4hi on my floor read shifter, but full time on my dash. So are 4hi in the 231 and full time in the 242 the same thing?

The 242 supports the following: 2HI, Fulltime 4WD, 4HI and 4LO. The only ones appropriate for the road are 2HI and Fulltime. So the difference between Fulltime and 4HI is that Fulltime differentiates front/rear to allow for good road manners when traction is available, 4HI is locked front/rear on most cases and will cause binding and hopping in tight turns, and eventually damage to the transfer case and drivetrain components.

It's pretty close to the same thing. Basically full time was ment for the rain and slick road conditions.

Not really IMO. Fulltime is meant for everything, hence the name fulltime. It's appropriate for most road conditions. You could use 4HI in rainy and slick conditions if traction is poor enough. Fulltime is kind of 4WD for Dummies in my opinion.

 

[crimsonride]

Just FYI, the 231 can only be shifted on the fly if you have the non disco front axle. I.E. if your front driveline isn't already rotating don't try to jack it into four wheel on the move or you're going to get chunks.
Also, a full time T-case needs to be periodically driven in four high at least for 10-15 miles a month. Something to do with the condition of the VC.

 

[Ken]

K I gotta question. When I lifted my xj 8 inches at a friends house, we had to disconnected the rear driveline. When I went to drive it home 4hi wouldn't turn the front drive line, but full-time would, 4lo would too. What's the deal with the front drive line not turning in 4hi on a 242 case with the rear driveline out of the equation?

 

[crimsonride]

In four high you have a differential between the front and rear shafts to eliminate binding when you turn on a surface with good traction. They call this differential a viscous coupler, it's a limited slip diff. When you shift into four low it locks out this coupler making your front and rear shafts spin at the same speed no matter what.
When you tried to drive in high with the driveshaft removed it transfered all your power through the diff to your rear shaft that was removed. Hence, no moving till it's locked out.

 

[crimsonride]

When I went to drive it home 4hi wouldn't turn the front drive line, but full-time would, 4lo would too.

You meant to say part-time.

 

[Ken]

Your right about the part time. K I thought that the VC might have something to do with that. Thanks for the info.

 

[958mtm]

Full time is 4wd for dummies

I love full-time, I never use anything else unless I'm crawling or need more torque. I've never had a problem needing more direct traction and it rides so smooth you can barely tell it's there, i also never have a problem dis-engaging unlike part-time or 4lo. but like all things my experience with it will come to an end and i'm sure i'll like the 231 as well. I mean aren't all the cherokee's made after 91' or so using the 231?

HD242 sounds like it belongs in a cherokee to me, i'll have to look into that thanks

 

[JF1]

Just FYI, the 231 can only be shifted on the fly if you have the non disco front axle. I.E. if your front driveline isn't already rotating don't try to jack it into four wheel on the move or you're going to get chunks.
Also, a full time T-case needs to be periodically driven in four high at least for 10-15 miles a month. Something to do with the condition of the VC.

Not quite. My '90 has the 231 and is a disco front axle and I can shift into 4hi at any speed. I've been doing it seasonally and on dirt roads since I bought it new in '90. My owners manual even says that you can shift into 4hi at any "reasonable speed". I've got over 330K miles on this transfercase.

 

[crimsonride]

Not quite. My '90 has the 231 and is a disco front axle and I can shift into 4hi at any speed. I've been doing it seasonally and on dirt roads since I bought it new in '90. My owners manual even says that you can shift into 4hi at any "reasonable speed". I've got over 330K miles on this transfercase.

Really? that's interesting. I wonder how it does that? You're engaging the intermediary shaft and front drive shaft along with the chain from 0 rpms to say 2500 rpms instantly. Maybe there's something I'm missing.

 

[Brad]

Really? that's interesting. I wonder how it does that? You're engaging the intermediary shaft and front drive shaft along with the chain from 0 rpms to say 2500 rpms instantly. Maybe there's something I'm missing.

The vac-disconnect only disconnects the passenger-side shaft. The driver-side axle is still spinning the R&P and driveshaft.

One more thing to note is that a fulltime 4WD system usually utilizes CV-joints (weak) in the axleshafts to eliminate front end vibrations at high speeds.

 

[crimsonride]

The vac-disconnect only disconnects the passenger-side shaft. The driver-side axle is still spinning the R&P and driveshaft.

One more thing to note is that a fulltime 4WD system usually utilizes CV-joints (weak) in the axleshafts to eliminate front end vibrations at high speeds.

Sure about that? Not the case on mine. If that were the case you'd have a pull to the left on freeway like when you install a locker. Also, I'm pretty sure the spider gears would spin before the entire driveshaft and chain assembly.