4WD won't disengage aka stuck
08-17-2005, 03:33 PM
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4WD won't disengage aka stuck
Anyone else have these troubles with your push-button type 4WD ? (FYI, I'm talking about a '99 Ltd.)
When the button on the X'fer case lever is pushed in (in 2H/4H), normally the dash indicator will flash until the process of engagement is complete, then stop. Mine doesn't stop flashing. But, it's obvious that some or all of the diffs. in the drivetrain are locked as sharp turns result in all kinds of binding and skidding, etc. When I try to disengage the 4WD stuff, nothing happens. Things stay locked and the indicator continues flashing, even after the recommended maneuvers of Reversing and or accelerating to disengage.
The first time this happened, after a couple of days of driving it like this, went to dealer, but it fixed itself after I gave it to 'em. Yes, indicator stopped flashing too. Figures. The second time, it "fixed" itself when I hit a pothole while driving it.
Obviously, something is sticking or some actuator is not actuating.
What's the most common/likely culprit for me to check first ?
When the button on the X'fer case lever is pushed in (in 2H/4H), normally the dash indicator will flash until the process of engagement is complete, then stop. Mine doesn't stop flashing. But, it's obvious that some or all of the diffs. in the drivetrain are locked as sharp turns result in all kinds of binding and skidding, etc. When I try to disengage the 4WD stuff, nothing happens. Things stay locked and the indicator continues flashing, even after the recommended maneuvers of Reversing and or accelerating to disengage.
The first time this happened, after a couple of days of driving it like this, went to dealer, but it fixed itself after I gave it to 'em. Yes, indicator stopped flashing too. Figures. The second time, it "fixed" itself when I hit a pothole while driving it.
Obviously, something is sticking or some actuator is not actuating.
What's the most common/likely culprit for me to check first ?
08-17-2005, 09:45 PM
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This is a copy of what I wrote to another member, I'm too lazy to retype 
. This should get you in the right direction. 
Long story short, my problem ended up being a combination of a bad xfer case AND bad sensors. I spent hours with mechanics, paid the stealer to look at it and they gave me nothing. I got fed up and bought myself a FSM and a multimeter and spent hours learning the system inside and out and I finally tracked down the problem.
The very first thing that you'll want to check are all the sensors/actuators (people call them different things). 99% of the problems in these AWD/4WD setups are caused by one of these failing, or a bad vacuum line. So you want to check these out first.
Off the top of my head there should be 6 sensors total. One on the front DIFF kind of in the back and underneath (easy to get to with skid plate off), two sensors are on the very back driver side of the xfer case on top of that little motor assembly (that thing engages your front driveline), then three total on the top of the tranny hump (2 drivers side, 1pass side). The only way to get to the ones on the top of thr hump is to unbolt the x-member and lower the tranny as far is you can, then I cut and 11/16" wrench in half and used the round end to get them out. Its a tight fit.
To test them they are basically little metal buttons with two wires connected. When the button is pressed you should have a complete circuit, when not pressed, no circuit. I just took a multimeter to each one, clipped onto the pins, set to measure for impedance, then just pushed the buttons. The important thing here is just that you get a definite 0 impedance when not pressed, and you immediately get a solid reading when pressed. If its iffy at all I'd replace them.
I'd definitely start with the front DIFF, its the most likely to go bad. These things run $60+ I believe new, but a local salvage yard should have them for much cheaper, just make sure you test them first.
I'm assuming that the sytem has been working up till now, so make sure you keep the washers with the sensor as you pull them out. Sometimes they will stick to the case and you my accidently double stack them, or lose one, and this would throw off the travel distance of the button.
The only real way to check the vacuum lines out is with a hand pump, so if you can get your hands on one I'd check that out as well. Just basically put 20psi of vacuum on each of the two lines and see if it bleeds down. The lines come up on the fender next to the battery. There's a Blue and Brown solonoid, each has one line that goes down to the diff, those are what you want to check.
I hope this makes sense, feel free to ask if you need me to clarify anything.
Good Luck!
. This should get you in the right direction. Long story short, my problem ended up being a combination of a bad xfer case AND bad sensors. I spent hours with mechanics, paid the stealer to look at it and they gave me nothing. I got fed up and bought myself a FSM and a multimeter and spent hours learning the system inside and out and I finally tracked down the problem.
The very first thing that you'll want to check are all the sensors/actuators (people call them different things). 99% of the problems in these AWD/4WD setups are caused by one of these failing, or a bad vacuum line. So you want to check these out first.
Off the top of my head there should be 6 sensors total. One on the front DIFF kind of in the back and underneath (easy to get to with skid plate off), two sensors are on the very back driver side of the xfer case on top of that little motor assembly (that thing engages your front driveline), then three total on the top of the tranny hump (2 drivers side, 1pass side). The only way to get to the ones on the top of thr hump is to unbolt the x-member and lower the tranny as far is you can, then I cut and 11/16" wrench in half and used the round end to get them out. Its a tight fit.
To test them they are basically little metal buttons with two wires connected. When the button is pressed you should have a complete circuit, when not pressed, no circuit. I just took a multimeter to each one, clipped onto the pins, set to measure for impedance, then just pushed the buttons. The important thing here is just that you get a definite 0 impedance when not pressed, and you immediately get a solid reading when pressed. If its iffy at all I'd replace them.
I'd definitely start with the front DIFF, its the most likely to go bad. These things run $60+ I believe new, but a local salvage yard should have them for much cheaper, just make sure you test them first.
I'm assuming that the sytem has been working up till now, so make sure you keep the washers with the sensor as you pull them out. Sometimes they will stick to the case and you my accidently double stack them, or lose one, and this would throw off the travel distance of the button.
The only real way to check the vacuum lines out is with a hand pump, so if you can get your hands on one I'd check that out as well. Just basically put 20psi of vacuum on each of the two lines and see if it bleeds down. The lines come up on the fender next to the battery. There's a Blue and Brown solonoid, each has one line that goes down to the diff, those are what you want to check.
I hope this makes sense, feel free to ask if you need me to clarify anything.
Good Luck!
08-22-2005, 07:24 AM
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Thanx to all...
Thank you to all who sent in their 2-cents (and yoda_g2 who sent in at least 6-cents worth !). After using all the suggestions that were relevant to my '99 Ltd. I finally had to resort to having a real mechanic look at it. Turns out that there is something mechanical INSIDE the transfer case that is busted, locking-up the whole 2W>4W>2W shifting thing ! Oh well....
08-22-2005, 10:31 AM
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Originally Posted by runn4runn
Thank you to all who sent in their 2-cents (and yoda_g2 who sent in at least 6-cents worth !). After using all the suggestions that were relevant to my '99 Ltd. I finally had to resort to having a real mechanic look at it. Turns out that there is something mechanical INSIDE the transfer case that is busted, locking-up the whole 2W>4W>2W shifting thing ! Oh well....
Lol, no problem. Glad you got it figured out. Sounds like you may have had the same issue that mine had.
Good Luck!
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