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Why a NP242 over the NP247? - Printable Version

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+--- Thread: Why a NP242 over the NP247? (/showthread.php?tid=553)

Why a NP242 over the NP247? - 28this - 04 May 06

I have the NP247 in the WJ. I was researching online the differences between the two from it being mentioned about swapping my 247 for a 242. From what I see in the two charts below, wouldn't you want to stay with the 247 over the 242? From what I see, it can take more torque and has better transfer power to tires. I do know the 1998 ZJ grand Cherokee with the 5.9L in it has the exact same t-case mine does instead of the 242. For those that don't know, the 5.9L in the ZJ puts out 345 FT/LB of torque. If the 242 is better, why didn't they use it?

Well, look over what I have here if you don't mind and tell me what your opinion is and why.
Type 2: NV247 Quadra-Trac IITM
[Image: quadra2s.jpg]

[Image: qt_shifter_01s.jpg]
  • Type: Progressive On Demand
  • Full time 4WD operation sends power to both the front and rear axles under normal driving conditions and automatically transfers torque to the front as needed
  • Gerotor pump in the transfer case transfers power immediately to the front axle when wheel slip is detected. provides four-wheel drive power automatically, with no driver input
  • Includes a low-range mode for severe road conditions and low-speed pulling power
  • Includes a neutral mode that allows the vehicle to be towed
The NV247 is an on-demand 4-wheel drive transfer case with two operating ranges and a neutral position. Under normal driving conditions, the system operates conventionally, and the majority of available torque is applied to the rear wheels. However, when front-to-rear wheel speed variations exist, the progressive differential transfers torque to the axle withthe better traction, thus minimizing wheel spin and maximizing control.

Operating Modes:
4WD High, full-time (Sends power to all wheels)
NEUTRAL (Allows vehicle to be towed)
4WD Low, part-time (Doubles the transfer case gear ration for severe road conditions and low-speed pulling power)

Low Range Ratio: 2.72:1
Center Differential: Gerotor pump-applied disc clutch with low-range lock
Torque Split: Variable (0-100%)
Maximum Capacity Torque: 1800 lbs.-ft.
Weight: 83 Lbs.
Oil Fill Capacity: 2.5 pts.
A circular ID tag is attached to the rear case of each transfer case. The ID tag provides the transfer case model number, assembly number, serial number, and low range ratio. The transfer case serial number also represents the date of build.

[Image: nv_247_01s.jpg]
NV-247 Fill and drain plug locations [Image: tcase_qtrac_01s.jpg]
NV-247 Quadra-Trac drive system

Type 3: NV242 Selec-Trac®
[Image: nv242_1s.jpg]

[Image: st_shifters.jpg]
  • Type: Full-time
  • Full time 4WD operation sends power to both the front and rear axles under normal driving conditions.
  • Open center differential enables four-wheel drive operation on any road surface.
  • Shift-on-the-fly capability allows switching between two-wheel drive, part-time high range 4WD and full-time 4WD, at speeds up to 55 mph
  • Available Trac-Lok limited-slip rear differential with torque-sensing device for maintaining traction on slippery surfaces. Automatically distributes torque to the rear wheel with the most traction, thereby reducing wheel spin at the other wheel
The NV242 provides full time 2-wheel, or 4-wheel drive operation. A differential in the transfer case is used to control torque transfer to the front and rear axles. A low range gear provides increased low speed torque capability for off road operation. The low range provides a 2.72:1 reduction ratio

The 2WD and 4x4 full time ranges can be used at any time and on any road surface. The 4x4 part-time and 4 Lo ranges are for off road use only. The only time these ranges can be used on hard surface roads, is when the surface is covered with snow and ice.
The geartrain is mounted in two aluminum case halves attached with bolts. The mainshaft front and rear bearings are mounted in aluminum retainer housings bolted to the case halves. Two versions of the NV242 are used in the WJ vehicles, NV242LD and NV242HD. The two transfer cases can be distinguished from one another by the rear output shaft retainer. The NV242LD uses a rubber boot to cover the rear output shaft, while the NV242HD uses a cast aluminum housing.
Operating Modes:
2WD (Sends all power to rear wheels)
4WD High, full-time (Sends power to all wheels)
4WD High, part-time (Locks both front and rear driveshafts for increased traction)
NEUTRAL (Allows vehicle to be towed)
4WD Low, part-time (Doubles the transfer case gear ration for severe road conditions and low-speed pulling power)

Low Range Reduction Ratio: 2.72:1
Center Differential: Open, Planetary with low-range lock
Torque Split: F/R 48/52
Maximum Capacity Torque: 1486 lbs.-ft.
Weight: 86 Lbs.
Oil Fill Capacity: 2.85 pts.
A circular ID tag is attached to the rear case of each transfer case. The ID tag provides the transfer case model number, assembly number, serial number, and low range ratio. The transfer case serial number also represents the date of build.

[Image: nv_242_01s.jpg]
NV-242 Fill and drain plug locations [Image: tcase_selec_01s.jpg]
NV-242 Selec-Trac drive system

Why a NP242 over the NP247? - 28this - 05 May 06

There has got to be some Jeepers out there with something to say about this thread. I am really curious to know what makes the 242 better than the 247, cause from what I have found, the 247 would be the better of the two.

The 231 was also mentioned for a swap, but I don't think it would work with my outfit. The 231, from what I have found is designed for the lighter jeeps like the CJ's and Wranglers. Could it actually work in mine? If so, what makes it better also? :feedback:

Why a NP242 over the NP247? - SHoppe715 - 05 May 06

First off, that's some excellent tech info research.

This is only my :2cents: but I think it's just because of the shifting / drive mode features and not a strength / durability issue. Let's be real... less than 1% of grand cherokees really get wheeled and even less get modified. Either case is plenty strong for the stock setup and expected usage. The two different systems are simply a selling point / option that people want for the same reasons they look for cup holders and trunk space.

If I were to lift and wheel one I'd want QTrac II over Selectrac. I just think there's too much that can go wrong when it gets that complicated. Sure, Selectrac gives you 2hi... better gas mileage, but is 5mpg really an issue when you add a couple hundred pounds of bumpers, skid plates, a winch, bigger wheels, etc.?

Why a NP242 over the NP247? - 28this - 05 May 06

Good :2cents: Shoppe. I guess mine falls in the less than 1% since mine will get wheeled and it is now lifted. I would like the capability of 2wd, but I like the sounds of the more durable t-case.

Why a NP242 over the NP247? - SHoppe715 - 05 May 06

SHoppe = Steve Hoppe = Steve

Why a NP242 over the NP247? - 28this - 05 May 06

Hello Steve.

28this=check vehicle registration, but you can call me Bryant.

Why a NP242 over the NP247? - 28this - 06 May 06

Btt