dernt

I have a 99 Cherokee with an NP242. It is not engaging 4wd in fulltime high or parttime high, but it is engaging in 4WD low. Any ever have this happen? What was the fix?

cruiser54

Shifting it properly?

Here's how the factory suggests you shift the transfer case and I've been doing this since these things were new and I worked at the dealership. Quoted from the owner's manual. The suggestions in CAPS are mine.

"To engage, shift the transfer case lever from 2H to 4H while the vehicle is moving at any legal speed". I LET OFF THE GAS, THROW THE LEVER, TAP THE GAS AND LET OFF.

4L position: " To engage, slow the vehicle to 2-3 MPH , shift the transmission to Neutral, then shift the transfer lever to the right and pull firmly rearward to 4L".

TO SHIFT OUT OF 4L, SHIFT THE TRANSMISSION INTO NEUTRAL WITH THE VEHICLE STOPPED, SHIFT THE TRANSFER CASE LEVER TO 2H, THEN THE TRANS TO D IF YOU HAVE AN AUTOMATIC, OR INTO FIRST GEAR WITH A MANUAL, AND CONTINUE ON.

Revised 11/20/2014

dernt

From a dead stop, shifting into 4WD part time high or 4WD full time high will not engage 4WD. Shifting into 4WD low will engage to 4WD. I've got and XJ with a 231, and a KJ with a 242 that work as expected. My XJ with a 242 is the one that's acting up. I don't think it is my shifting technique.

cruiser54

Try it. I've never has a 242 that shifted worth a crap without using the factory recommended technique.

And not just MY 242's, but the hundreds of customers I had as Service Manager at a Jeep dealership from 1980 through 1992. It's unlike the 231 as far as ease of shifting at a stop, although the 231 should be shifted the same way ; on the fly.

SteveMongr

My 242 only likes to engage Full and PartTime when transmission is in neutral. I do not come to a stop, just shift transmission into neutral, shift TC into 4, then shift back into D.

ehall

Same for me, I have to unload the transmission before the transfercase will fully shift. Note that the light comes on after the shift completes. Sometimes just bumping it through the gears is enough to complete the shift.

FWIW, FT/PT uses the rear mode fork, while hi/lo uses the front mode fork. They are completely separate from each other. If the front output is engaged in any mode it will be engaged the same in every other mode that uses it.

dernt

I'll give it a try. My lever does move, and clicks into place, and the dash indicater comes on, but no power to the front axle. I'll let you know if this shifting procedure resolves my issues.

CCKen

You may have a problem with your differential. The 242 differential is a touchy device. The transfer case gear train should be unloaded and free wheeling when shifting this TC. The vehicle should be moving forward and when shifting let off the gas then shift.


The teeth leading edges on the mode sleeve that engages the differential are square and so are the teeth on the inside of the mainshaft gear (poor design that was fixed in the Hummer 242 - tapered leading edges) so they have a hard time engaging unless the mainshaft if turning. Shifting the trans to neutral when shifting to 4LO is mandatory in my book but not mandatory when shifting to other gear ranges.


To see if your differential has suffered damage from gear teeth clashing, drain the TC fluid in to a clean shallow container then look for gold (bronze actually) flakes floating around the fluid. If you see a lot the differential has been subjected to the mode sleeve/mainshaft gear clashing and the steel bits have gotten in to the bronze ring in the differential. The leading edge teeth may be beyond use.

SteveMongr

Thank you CCKen for detailed technical information! It's always helpful to understand how something works.

To add to my earlier post, due to the shift issue I replaced the stock 242-J with a fully re-manufactured 242-WJ. Same exact issue again. Tried adjusting the linkage but it was already dialed in and the bushings are tight.

dernt

I don't understand it, but this seems to resolve the problem that I was having.

ehall

Think of it like a bicycle, easier to shift when the sprockets are turning

cruiser54

good analogy.

dernt

The part I don't understand is that it clunks into position, but is not in 4wd. I get the whole synchronizing gears.

cruiser54

Just shift it the way it's supposed to be shifted and enjoy it......