Swampy, this ain't the first time an auto technician was wrong about something! <img src="/forums/images/graemlins/lol.gif" alt="" />

Swampy said "I guess I was misunderstood... I did mean no going over 35 on DRY GROUND.. and no you absolutly cannot shift the 242 on the fly.. IF you go from open 2WD to locked 4 part time (which is the first selection ) at speeds you will do damage to something .. Part time is exactly that.. Designed to be used Only PART of the time.. IF you are driving normally down the road you should be in Full time.. "

What we are discussing here is the selec-trac transfer case ... it has 5-modes ... 2WDH, N, 4WDH-part time, 4WDH-full time, and 4WDL.
4WDL locks the front and rear drivshafts to rotate at the same speed, the owner's manual warning is "not to exceed 25 mph" in 4 low where in this setting "the engine speed is approximately 3-times that of the 2H and 4H" settings; "take care not to overspeed the engine and do not exceed 25 mph". Shifting from 4H to 4L or 4L to 4H, the owner's manual reports "the preferred method is with the vehicle rolling 2 to 3 mph; with the vehicle rolling at 2 to 3 mph, shift an automatic transmission to neutral, and with the vehicle coasting at 2 to 3 mph, shift the transfer case lever to the desired position and do not pause in the transfer case neutral."
"Selec-trac transfer case is equipped with an inter-axle differential which allows the vehicle to be driven in 4 full time position at all times on any given road surface", "the 4 full time mode allows the front and rear wheels to rotate at different speeds which eliminates driveline binding and component wear". "When additional traction is required the 4 part time and 4LO positions can be used to lock the front and rear driveshafts together through the transfer case inter-axle differential and force the front and rear driveshafts to rotate at the same speed."
"Driving in the 4 part time and 4LO positions on dry hardsurfaced roads may cause increased tire wear and damage to the driveline components."
"Shifting between 2WD and 4 part time can be made with the vehicle stopped or in motion. If the vehicle is in motion, shifts can be made up to 55 mph. With the vehicle in motion two momentary releases of the accelerator pedal may be required after shifting. This will induce a torque interrupt and allow full engaugement of the newly selected position. With the vehicle stationary it may be necessary to shift the automatic transmission from drive to reverse and then back to drive after shifting. This will allow full engagement of the newly selected position."
"Shifting between 4 part time and 4 full time can be made with the vehicle stopped or in motion. If the vehicle is in motion shifts can be made up to 55 mph." Other procedures for shifting between 4 full time and 4 part time are the same as written above.
This notion that 4 part time is only for part time use . . . that means when additional traction is required for loose, slippery road surfaces ... if your offroad on loose gravel or slipper rocks, snow and ice, rock crawling, muddin, sand dunes, etc. ... you can be in 4 part time mode all the time, all day long! 4 part time mode should not be used on dry hard road surfaces. <img src="/forums/images/graemlins/cheers.gif" alt="" />

Swampy said "Just so you know.. Or incase you dont.. You should never go over 35 in parttime.. IF you have been doing that you are killing your t case.." <img src="/forums/images/graemlins/lol.gif" alt="" />

This is wrong! We know that you should not shift to 4 part time on dry hard road surfaces. On slippery road surfaces, such as snowy or heavy rain conditions, you certainly can drive over 35 mph!

Swampy said "For normal everyday driving in 4 you want 4 fulltime.." <img src="/forums/images/graemlins/lol.gif" alt="" />

For normal highway driving, you should be 2WD, but you can safely drive in 4 full time mode.

And, then ... Swampy said "Should be rolling under 5mph put tranny in N then pull the shifter into 4.. Same for going back.. Rolling tranny in N push up into 2 and resume.." <img src="/forums/images/graemlins/lol.gif" alt="" />

See the post above in regards to owner's manual shifting instructions.

Swampy, I'm sorry, but I just had to address the wrong information you provided above. You probably meant well and want to help, but, please, check your info before posting.
<img src="/forums/images/graemlins/cheers.gif" alt="" />

I have driven my ZJ for well over 130k miles and have shifted while on the fly many many times with no ill effects. I even cornered a New Venture engineer at Camp Jeep and specifically asked him if there was a top speed for shifting and he said there was not.

Well I have 150,000 on my jeep Most of it pretty hard wheeling and about 40,000 of that with a 242 ....AND 15 years of working on jeeps AND ........ I dont care what an engineer said.<img src="/forums/images/graemlins/nana.gif" alt="" />.
I still think you will have trouble shifting your t- case at speeds like that because the 242 locks the front and rear in part time as well as in low.. And more importantly she still hasnt said whether her tires are exactly the same size and brand...

Cause when it comes right down to it whether I am wrong or not.. (Ok fine you pulled out the manual and proved me wrong <img src="/forums/images/graemlins/nana.gif" alt="" />) but thats not the point of this post..

We are suposed to be helping her figure out why her t-case is sticking and I still think its binding because she is driving around in Part time instead of full time...

But what do I know.. I am obviously wrong about everything else...

<img src="/forums/images/graemlins/lol.gif" alt="" />

Thank you guys for spending so much time proving that and no time trying to help her situation... <img src="/forums/images/graemlins/kewl.gif" alt="" />

Now I remember why I hate forums.... <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />

The word "exposed" comes to mind, as in the phrase "blow the whistle on"! <img src="/forums/images/graemlins/lol.gif" alt="" /> You have to admit, Swampy, if your Jeep mechanic with 15-years experience doesn't know how to shift the NV242 transfer case; and yet, wheels a ZJ having the 242 . . . perhaps it's time to find a new mechanic! <img src="/forums/images/graemlins/wink.gif" alt="" />
To your credit, you should note that nobody took exception to your information in regard to tire size.
I suspect that the transfer case is most likely being, or has been, shifted incorrectly, regularly.

Does the 242 have a synchro that engages the front shaft?


I know some 231's have one and some don't. If it does have a synchro for the front shaft I can see no reason why it cannot be shifted on the fly.

I know my 231 will shift smoothly at over 70 MPH with no ill effects on my T-case.

My shifting is fine. I only do driving in full time if in 4wd. I have heard all of the above after calling a jeep dealer and a different mechanic than my usual, my plan of attack:
1) get them to fix everything, and look over anything that might have been torn up.
2) get a whole new set of tires

it has been doing this for a while now. at first, only briefly get stuck in part time and kick out just about right away. but then i came up for inspection and needed tires only on the front... tire guys and the inspector were 2 different places and noone said a word about tire size effecting it that badly, but as soon as the jeep dealer told me about that little issue he had with his.... i realised it's only gotten 10 times worse since the 2 new tires. Thanks everyone... the beast is parked until my appointment and won't see the 4wd again until i have new tires.
I have never heard of the tire sizes effecting things so badly. Is it all 4wd's that are like that or is it just more prominant in cherokees??

That bullitin I posted is actually for 242's in Chevys..


And for the record.. I have been driving Jeeps since I was 12 I am 37 now and I have always shifted my T case the same way. (Just the way my dad showed me.) And I have never had a T-case issue that was related to shifting..(I have blown a few apart off road though:D.) Maybe I dont know what the manual says about how to shift a case , But I know how to do it just fine..



If you think I am not a good Mechanic ..Dont come to me .But I never said you wherent a top notch web wheeler so dont start trying to insult me.. <img src="/forums/images/graemlins/butwiggle.gif" alt="" /> :nana



And Willow.. FYI.. If you shift out of 4 and it doesnt disengage try stopping and backing up.I dont know what the manual says about that But It works sometimes...
And if the shafts are locked like It says in the bulletin I posted earlier.. Simply Jacking up the front of the Jeep and spinning the tires by hand will get it free.. I know you dont want to Jack up your Jeep everytime you park it but it will work to get you to 2WD right now..

Good luck..


Carl

I no longer have the 242..I swapped it in and It couldnt handle the horsepower I rebuilt it twice in the short time I had it in and finally I blew it to pieces on a rock pile.. <img src="/forums/images/graemlins/smile.gif" alt="" />
I have a 231D now ..
<img src="/forums/images/graemlins/kewl.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />

What kept breaking. I know the 249's have the viscouse coupler that where out, i though the 242 was fairly robust.