242 vs 249

[scott00tj]

Is the difference between the 249 transfer case and 242 is that the 249 is always in 4 wheel full time with no real 2wd, where the 242 is always in 2WD until shifted into 4full or 4part?

 

[joe_peters]

I think that is correct, but my GC knowledge is limited.

Article on various Jeep 4wd systems: http://en.wikipedia.org/wiki/Jeep_four_wheel_drive_systems

Are you considering swapping in a NP249? The viscous coupler of that transfer case is a major problem with its frequent failures.

 

[DieselSJ]

The 249 isn't a bad case. I know several teams that are using them very successfully in desert racing, with one of them behind a 550hp 401. They lack a lock in 4-hi so it limits their function if you are using it on the trails. I think they are a great case for street use in areas where you get snow, ice, etc...

 

[Tim_MN]

The viscous coupler of that transfer case is a major problem with its frequent failures.

The 242 with its mechanical differential for Full-Time 4x4 (instead of a viscous coupler) and the 2wd setting, makes it a better choice.

 

[scott00tj]

More just trying to understand, but I do want a 242 in my '99XJ.

 

[DieselSJ]

The 242 with its mechanical differential for Full-Time 4x4 (instead of a viscous coupler) and the 2wd setting, makes it a better choice.

I would prefer a viscous over an open mechanical diff. With the open diff you can still transfer all of the power to the single wheel that has the least traction. With the viscous you always get power going to both axles. The 229 has 2wd and viscous in 4-hi...problem is that it lacks a lock in 4-hi, it only locks in 4-low. Worked great in my diesel Waggy until I blew the viscous apart getting onto the freeway one day.

 

[Tim_MN]

The 242 has Full-Time (dry pavement) 4x4 with no viscous coupler, 2wd, Part-Time 4hi and Part-Time 4lo. Part-Time locks the front a rear axles together and bypasses the mechanical differential.

More good features than either a 229 or a 249, and without the pesky failure prone vicious coupler.

 

[gradon]

Two months ago I replaced a 249 with blown internals for a 242 in a neighbor's 99WJ(only cause there was a 242 WJ already sitting 2-3' higher on a stack of tires at the JY and the 249 WJ was on its rims=no brainer). Unfortunately, he let his unlicensed, barely legal, baby's momma drive it and she managed to roll it 2 weeks later. The 249 has two options: HI and LO. When I was doing my research, there were plenty of 249 horror stories. . .

 

[birchlakeXJ]

Not too familiar with the 249, but I absolutely LOVE my 242 selec-trac system.

When conditions are dicy (and they often are in MN winters), I can keep it in 4wd Fulltime and not worry about it as Fulltime 4wd can be used on any road condition, including dry pavement.

When I bought my 99, I sought out a 242 selec-trac specifically for the above reasons.

 

[jkrell]

Like Dieselsj said it all depends on application.

I drive a WJ with a 242 as my dailer driver and it is great. I've raced offroad the last 3 seasons in a vehicle with the 249. The 242 is a more complicated transmission internally where the 249 is a fairly simple and robust. A lot of people have had issues with the 249 on the street when the viscous burns up it fails to lock, but for racing the viscous will hold up for 1000 of miles.

Long story short if you are looking for all wheel drive with no 2wd option the 249 is a great way to go.

 

[Tim_MN]

.... A lot of people have had issues with the 249 on the street when the viscous burns up ......

Note that he said when, not if. Expect to to replace the viscous coupler at least once, if not twice, on a high mileage 249 or 229. The 242 is robust and reports of 242 problems are few and far between.

 

[winkosmosis]

Can you swap in the clutch pack 247 from the WJ or does it have fiddly electronics? I liked that case a lot... no need to shift to 4WD get 4 wheel traction, no need to shift to 2WD to prevent binding. There's no need for locked 4 hi when it effectively works just as well.