242 slips, and AW4 gets stuck in 1st?!?

So last week in Moab, we were going down metal masher. When i came up to a decently sized ledge i went to go up it and i hear this grinding noise from under my Jeep, and the back tires just dug in. At first i thought i had sheared teeth in my front D30, but with further inspection we figured out that i wasn't getting any power to the front wheels. The drive shaft was not moving at all.

I dealt with it all day, as that was the first ledge of the first trail of the trip i was not very happy. I thought that maybe my chain was slipping, which would be weird because we replaced it about 4 years ago with only a handful of times taking it off road.

Got back to camp and pulled the fill plug, it was a little low but not at all low enough to cause any problems. Maybe 1/8th of a quart low. I could see some gears and the teeth looked kind of rounded but it may be just how they are, not enough for me to think that i had found the problem.

It did this all trip, except some times it would work sometimes it wouldn't. And sometimes it would get you half way up the launch pad on golden spike and decide to give out on you 20 feet from the top... So because it would work some times we thought maybe the shifting linkage was shifting it too far or not far enough causing a small contact area and causing the loss of 4 wheel drive. Also i should mention it only did this in 4 lo, i tried it in the other 4 wheel drive modes but 4 lo was the only one giving me a hard time...

Now to the tranny, it's done this before but not for a very long time. Maybe last summer a bit. From a stop, it won't shift past 1st and sometimes 2nd. This happened to me today, i pulled over moved the shifter from park all the way back to 1-2 and back to drive and it got me home. I've checked the fluid levels and it's all good. I just don't understand what it could be as automatic transmitions are a level of tech knowledge i have yet to attempt.

Thanks for all your help, any advice is appreciated!

Had this in mod tech but realized i posted in the wrong place so i moved it.

I would check TPS.. as it is what the trans uses to shift. Also, check the TCu (under pass. side dash) see if the fuse is good, then unplug it and see if you can drive/manually shift the trans. If you can then it usually means the TCU is FUBAR'd

Johnnie Walker said:

I would check TPS.. as it is what the trans uses to shift. Also, check the TCu (under pass. side dash) see if the fuse is good, then unplug it and see if you can drive/manually shift the trans. If you can then it usually means the TCU is FUBAR'd

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I just replaced the TPS with a junk yard one and it seemed to be doing alright. I pulled like five of em so i guess i'll swap em out and see if that helps. I'll try your TCU check too, thinks for the advice.

is it possible the linkage is mis-adjusted and not getting you full engagement of 4-lo?

97XJ2 said:

is it possible the linkage is mis-adjusted and not getting you full engagement of 4-lo?

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That's what we thought and we tried adjusting it both back and fourth on the trail but i didn't notice any improvements and it didn't get worse either. Still just gave sporadic engagement and disengagement. I tried leaning on the shifter too, like pulling it back and pushing it forward. But no noticeable change. :dunno:
I'm totally confused with this... I've been toying with the idea of a Hummer H2 242 HD/ XJ 242 franken t-case replacement... But i can't justify that kind of money if it's not totally fubar.

<Bump>

Could the planetary set be Fubar'ed?

Guess i'll just have to crack it open when i've got a sec... Not looking forward to this.

Small update.. It decided to dump a half foot of snow on us and i went to drive my Jeep in part time and heard it slipping again, but when i put it in all time it doesn't slip and i had power to the fronts... Does this mean that whatever bypasses the diff in the t case for part time or 4lo is not engaging properly? Cause at first i couldn't get it to slip in part time, so i thought the problem was just with 4lo. But now it's any 4wd setting that locks the t case, or it could always have been and it just decided to work when I was testing it.

What i don't get is that it locked up enough for me to do my entire Moab trip consisting of some of the harder trails without major set backs, and it seemed like it would only slip under high stress conditions, like it gave me problems 3/4 of the way up the launch pad on golden spike(not fun backing all the way down i must say). But snow is a very low resistance condition where it doesn't take much to spin a tire, especially at normal psi and open diffs. But it slipped extremely easy. :dunno: