If you wonder whether your jeep needs a full-time NP242 or a part-time NP231 transfer case, take a look at this guide. Knowing the key differences and effects of installing a particular transfer case on your vehicles enables you to make a safe decision. Before you make a purchase, it’s crucial to find answers to some questions.
For instance, which one is better for you? What does it allow or not allow? And what will be its effect on the vehicle performance and your driving experience? If you are unable to figure out the most suitable option, I have good news for you. This NP231 vs NP242 guide will help you learn everything that you need to know before making a decision.
NP231 vs NP242 Transfer Case Comparison
NP231and NP 242 are two entirely different options since NP242 is a full-time transfer case and NP231 is only a part-time option. Both transfer cases show different potential in various driving conditions.
Before we jump to a comparative discussion of both transfer cases, let’s have a quick overview of both transfer cases.
What is NP242 Transfer Case?
NP 243 is probably the most versatile transfer case you can ever buy for your jeep. With an intuitive build and solid performance, the base unit has proved itself as one of the most rugged transfer cases on off-roading vehicles. This transfer case features 5 driving modes including full-time, part-time 4wd, 2wd, and 4wd.
The NP242 transfer case is identified by the red and silver tag on the rear of the case. The transmission compatibility and adaptability of the t-case are wide and it adapts very well to various factory transmissions including both automatic and manual options. The most famous transmission compatibility options for the NP242 are the SM465, T18, and TH400.
What Is the NP231 Transfer Case?
NP231 is a part-time transfer case that is found in many Dodge Rams, Wranglers, and SUVs. It is a solid transfer case option that is a sweet spot between reliability and performance. The transfer case comes with a solid aluminum body and chain drive making it a perfect option for everyday drive conditions.
In terms of power, it may not be a good option for big tires and high torque. The NP231 vehicle upgrades and modifications make it a perfect fit for various driving conditions. This T-case has the driver’s side front output and rear output. A low gear range is the receptacle of 2.83:1 which is probably the lowest in this range.
What Transfer Case Is Better: 231 Or 242?
| NP242 | NP231 |
| Horsepower: 243 hp | Horsepower: 265 hp |
| 6250 rpm | 6800 rpm |
| Full-time | Part-time |
| Lacks external locking hubs | The only part-time target case with external locking hubs |
| More gear options in low rage | Fewer gear options in the low range |
| 1-ton payload capacity | 2 tons payload capacity |
It is a little hard to say anything straight while comparing NP242 and NP231 since both transfer cases are built with different purposes in mind. NP242 being the full-time transfer case is much more powerful than the NP231 which serves as only a part-time transfer case.
NP242 has applications in more tough applications like hauling loads, heavy towing applications, and tough trail riding. It can add more power than the NP231 and also offer better tolerance against extreme temperatures. On the other hand, NP 231 has better aftermarket support. The fewer moving parts and extra switch clutches reduce the overall maintenance requirements and chances of damage.
NP242 with more moving parts and linkage bending problems can put you in trouble. The aftermarket support is not good for 242 and rebuilding costs can be higher. If you ride in tough conditions like snow, NP 242 is a better option, of course for its power. Putting the NP242 in full time definitely worth it on the snowy and slushy roads.
It eliminates the need of switching back and forth on snowy and plain roads. The torque rating of NP231 is good and the 231’s 3-pinion gear set is rated for 600-lb-ft. NP242 is more versatile since its application is large and it works in both full-time and part-time modes.
We can safely conclude that NP242 is a better option for off-roading, trail riding, and towing. However, for everyday rides and light-duty applications NP231 with its better aftermarket support, low maintenance requirements, and impressive torque rating may win the race. Here is a comparison table that will further help you get an idea of which transfer case suits your needs best.
Major Difference Between The NP 231 and NP242
- NP 242 is the full-time while NP231 is the part-time transfer case.
- NP242 uses 6 pinion gears in the planetary for low range while NP231 uses 3 pinion gears.
- NP231 front yoke chain is 1-inch wide and the NP242 chain width is 1.25 inches.
- NP242 has 5 detents while NP231 has only 4 detents making their shifters entirely different from each other.
- NP231 features external locking hubs and NP243 doesn’t.
- The RPM rating of NP231 is higher than NP242.
Are all NP231 Transfer Cases the Same?
Not all NP231 transfer cases are created equal.NP231 has a total of nine versions from 1983 to 2001. All the variants of the NP231 t-case are identified by the serial number. The serial number has a specific letter at the end.
The serial and part number of the transfer cases are usually mentioned on a sticker that is placed somewhere inside the transfer case. The nine variants of the NP231 transfer case are differentiated on the basis of the low-range gear readouts. NP 231 transfer cases from 1989 to 2001 are:
MP231, NP231A, NP231B,NP231C, NP231D, NP231E, NP231F NP231G, NP231H. NP231 being the oldest has no locking hubs and also lacks low-gear options. NP231A was equipped with internal locking hubs but it also doesn’t offer low-gear options. NP231C and later variants have low gear prevision and external locking hubs.
Frequently Asked Questions
Will a 231 fit my YJ?
The latest versions of the top 231 offer a direct swap with YJ if it was originally equipped with NP242. The older variant of the 231 transfer case will also fit YJs with a little modification to the mounting brackets.
How many splines is an NP231?
NP231 comes with 23 spline and 21 spline versions. Both of these spline options are available in long, short, and sometimes medium variations.
Is the NP231 a good transfer case?
NP231 is one of the most reliable transfer cases ever produced. With incredible torque output, external locking hub, and provision of low gear options it is one of the best transfer cases that you can have.
Which transfer case is better: internal v external lock?
External locking hubs are better than internal locking hubs since they have more potential for towing, pulling, and hauling. Internal locking hubs have the advantage that they tend to engage at very low speeds of around 1-2 mph. If you have a manual transmission, an internal locking hub is better, but in an automatic transmission, an external locking hub is a good option.
Wrapping Up
I’m hopeful that this comparison guide will enable you to figure out what transfer case is best for your vehicle. If you are still confused you can put your queries on big jeep forums to get more concrete solutions. The choice of the transfer case highly depends upon the driving condition in which you mostly drive.
Hi! Ulberto Williams here, a passionate adventurer who has been driving jeeps all his life. My passion for the thrill of off-roading has allowed me to learn what modern-day jeeps have to offer. Exploring the popular trails and seeking thrills in the unexplored terrains allowed me to discover the true intimacy nature had to offer and become an avid learner of Off-roading with Jeeps. Hence, I decided to create this blog to share my experiences of jeep riding and off-roading with the world. My only goal is to provide the readers with quality reliable information about jeeps.