Stuck in Part Time 4WD

[Pauldownunder]

96 Cherokee with Slect Trak transfer case. After driving in Full time 4WD and trying to go back to 2WD, it has got to Part time 4WD and stayed there. The transfer lever is all the way back to 2WD but the shift hasnt happened.
Have tried stopping and starting, reversing etc but it wont shift.
I have heard that tire pressure or size can sometimes effect the transfer shifting. I have just had 2 new Pirelli Scorpion ATs put on the back wheels which dont match the front tires which are BF Goodrich Macadems. The sizes are the same though 235/75/15, could this have any bearing on the problem.
(before you ask the 2 Pirellis were a gift, hence the mismatched set).
Also, is it ok to carry on driving in Part Time 4WD until I get the problem fixed?

[gtmud]

First, NO, its not a good idea to drive in part-time 4wd! The best thing you could do, if you HAVE TO DRIVE IT, is to disconnect your front shaft, actually, how do you know that your still in 4 PT. You might actually be in 2wd and your indicator is showing differant. To test this theory, turn the wheel al the way to one side, SLOWLY move forward, if your still in 4PT then you'll feel the front axle bind. then your defiantly still in 4wd, and need to park it till you fix it. Or jack the entire XJ in the air, transmission in nuetral, rotate the rear tires(driveshaft, does the front driveshaft turn too? If so your in 4 wd still. Also check all your linkage for loose connections that might be throwing off your disengagement.

[[Fe]weapon]

linkage loose or out of adjustment
do you have room to pull past 4 low?
if you do you can adjust it underneath to get 2 high back
if you dont you likely have play in the linkage as gt mentioned
(quick fix)underneath the truck manually shift the tcase out of 4
find the lever that comes out of the tcase have a friend push towards 2 high, watch the linkage direction then give the tcase lever a little nudge in that direction with a screw driver or long extension(i believe it will be up and back) you will likely feel it click into place that will get you moving again till you can sort out the problem without having to remove the driveshaft.

I have to do this everytime I leave the trail because I lowered the skidplate to accomodate drive angles and have not yet lowered my linkage to compensate

hey GTmud can you post some pics of you rig?

[Pauldownunder]

Thanks for the tips. Last night I tried something very similar to what gtmud suggested. I moved the Jeep forward slightly and turned the wheel and the front axle was definately binding. I got underneath to check for any loose/damaged connections and from a quick once over they looked ok but may need a better look.
Anyway, I then jacked up the back of the jeep and rotated the rear wheels a few turns, lowered it back down, started her up and magically it was back in 2WD.
Took it out for a drive, engaged Ft 4WD which was ok, then tried to go back to 2WD and it got stuck in Pt 4WD again! Redid the jacking and wheel turn and once again its fine.
PS -[Fe]weapon - There is no extra room for the transfer handle to move forward
At least for now i know a temporary fix, but would like a permanent one. Any more thoughts?

[JDPascal]

From what you have said and what has been suggested, the tires you now have could be a factor.

Did you have the same shifting problem before the tire change??

Same sizes from different manufacturers can have different rolling radius at similar inflation pressures. Add to that the different tread wear levels between the two and you get the binding.

Thats why I've always heard that you put on a set of 4 tires on a 4wd.

A fiddly check would be to borrow mama's sewing tape and drive over it to about the middle - measure the loaded circumference of each tire and inflate so that they are all the same. Drive it after you've matched all 4 and see if you still have the shifting problem

A process like this is recommended to achieve this equal size condition when fitting used tires to a tandem truck. They measure all the tires for the drivers and all 8 have to be within 1/4 inch diameter or 3/4 inch circumference for a 11.00/22. All this is to keep the 3 diffs in the tandem from overheating. After all this matching and more that I haven't told you, they adjust the tire pressure to minimize the temp in the diff oil

If the big trucks are worried about a 1/4" diameter causing a problem on those big tires, you could be easily accumulating a 1/4" diameter difference with different makes, wear and inflation.

Just a thought..........

JD

[Pauldownunder]

Thanks JD
The problem has only started since the 2 new tires went on which is why I was a bit suspicious. Was planning to get 2 more to match next month anyway, so I think i'll just get them now. Will let you know the result.

[[Fe]weapon]

ya that'd do it alright