4x4 Problems

[jbish1572]

I have a 2000 ford explorer xls. It has: Auto, 4x4 high,4x4 low selector nob
It work find in all positions. I had the transmission rebuild and now only auto and 4x4 high works. 4x4 low does not work. No sound no clicking. It is almost like all of the conditions is not being met (in neutral, breaks) but I do put it in neutral and I do hold the breaks. Anyone have any idea of what might of happen? Is there a safety circuit that might have gotten unplugged and not plugged back in so the module thinks it is still in gear?

 

[BrooklynBay]

Welcome to this forum! Check the adjusting linkage going to the transfer case. Maybe it got out of alignment when they did the transmission work.

 

[IZwack]

A non-working 4LO is often attributed to a failing shift motor at the transfer case.

But personally, I wouldn't worry about it -- 4LO just leads to more trouble (like not being able to get out of it). 4HI is enough for 99% of the drivers out there as the extra torque provided by 4LO is not really needed.

 

[jbish1572]

I would agree with you except that it worked fine before the transmission was rebuilt. Now it does not work. I just don't see how the shift motor could have went bad after the rebuild. I could see if it was months or weeks, but I am talking about the same day. it worked the day before, transmission gets rebuilt, I go pick it up, try the 4x4, it all works but the 4x4 low.

 

[BrooklynBay]

Did you take it back to the shop after they installed the transmission?

 

[jbish1572]

I am supposed to bring it back today around lunch time, but he wasn't for sure what could cause it either. So I thought I would do a little research and see if I can't help him out a little.

 

[BrooklynBay]

In addition to checking the linkage, check the electrical connections on the module, and the shift motor. If the connector got yanked, it might cause one side to lose contact while the other side is fine.

 

[jbish1572]

Just got back and had him check it. He took the shift motor out held it in his hand and had me to turn the ignition on(not start) and put the transmission into neutral and then switch the nob. He said the motor should turn a little, but he said it didn't. So he is thinking maybe a ground problem he said. To me, I thought that if I turn the nob from Auto to 4x4 high and in order for the light to come on a sensor has to be press or tripped, and the only way for that to happen is if the motor is turning. I am lost, It work find before now no Low.
Any other ideas what could be causing it?

 

[IZwack]

The shift motor does not move when shifting into 4HI - it only moves when shifting into 4LO. 4HI engagement is purely electronic, there are no direct moving parts. 4LO on the other hand requires a mechanical change and that change is controlled by the shift motor.

Read this:
http://www.explorerforum.com/forums/showthread.php?t=203441

 

[jbish1572]

Ok, so that make sense why he didn't see it moving. So some reason the motor is not turning and it had to do with him taking out the transmission and rebuilding it and putting it back in. Because everything worked great before hand.

Have any other suggestions?

 

[IZwack]

So some reason the motor is not turning and it had to do with him taking out the transmission and rebuilding it and putting it back in. Because everything worked great before hand.

The shift motor is not touched during removal of the transmission. So I dunno what to tell you other than check the connectors because that's the only thing that they would get their hands on (it needs to be disconnected to remove the transfer case). Also keep in mind that these motors are somewhat temperamental and will just one day stop working (maybe corrosion from rain/snow?). This is one of the reason why I think people should stay away from 4LO, it only leads to problems (half the time, driver’s don’t know the procedures of shifting into 4LO and/or they use 4HI/4LO on dry pavement which puts excessive forces on the transfer case’s internals causing premature wear/damage).

 

[jbish1572]

I don't think that corrosion could have caused it because I had the transmission rebuilt done yesterday and as soon as I got home I tried it and that is when I noticed the issue. The mechanic said that it is weird that it isn't working because they didn't mess with the transfer case but he said he did know it worked before because he tried it all before he did the rebuild. So something happen.

 

[IZwack]

I don't think that corrosion could have caused it because I had the transmission rebuilt done yesterday and as soon as I got home I tried it and that is when I noticed the issue. The mechanic said that it is weird that it isn't working because they didn't mess with the transfer case but he said he did know it worked before because he tried it all before he did the rebuild. So something happen.

How did you test it the day before? And how did the mechanic test it? Because engaging 4LO or 4HI (as stated) on dry pavement will kill the transfer case.

Either way, the transfer case now needs work -- whether thats the motor or the internals of the case itself. Your mechanic should know how to diagnose and fix the transfer case.

 

[Sams01XplrSprt]

welcome

 

[jbish1572]

I had to back my boat up a gravel hill. My reverse was pretty much shot but it would work in 4 lo. So I was able to back the boat up. When he tried it, he did tried it on his gravel parking lot.
Anyways the vehicle will not start now. It was running find except for the 4lo. I parked it on a hill like I always do and when I got back in to start it no start. The lights on the dash lite up, but it acts the same as trying to start it in gear. So I figured that maybe the linkage is messed up, I start looking and It all looks good. I take the plug off of the switch, thinking maybe it is not making contact and when I go to put it back it I notice that the pin is bent. So I try to take the switch off. I remove the center big nut and the 2 bolts and try to pull it off and it does not come off. In the hanes manual it says that the cuts in the plastic should line up with the cuts in the shaft coming from the transmission. They don't. I end up having to break the switch just to get it off. What doesn't make sense is that he hooked his snap on scanner to the vehicle when I tool it to him the other day and it show all the gears when you move the gear shift. I don't see how the it could all of sudden stop working.

 

[jbish1572]

Got the problem fixed. It was the safety neutral switch. He said that he might of got moisture in it when he cleaned the transmission. Now the explorer starts and 4 lo works like a charm.

 

[gijoecam]

A little late getting in here, but I figure I can clarify a couple things...

Just got back and had him check it. He took the shift motor out held it in his hand and had me to turn the ignition on(not start) and put the transmission into neutral and then switch the nob. He said the motor should turn a little, but he said it didn't. So he is thinking maybe a ground problem he said. To me, I thought that if I turn the nob from Auto to 4x4 high and in order for the light to come on a sensor has to be press or tripped, and the only way for that to happen is if the motor is turning. I am lost, It work find before now no Low.
Any other ideas what could be causing it?

The shift motor does not move when shifting into 4HI - it only moves when shifting into 4LO. 4HI engagement is purely electronic, there are no direct moving parts. 4LO on the other hand requires a mechanical change and that change is controlled by the shift motor.

Read this:
http://www.explorerforum.com/forums/showthread.php?t=203441

IZ was right on here... Although the tech may know transmissions, they're seldom knowledgable about the inner workings of our transfer cases... I have yet to find a trans tech I didn't have to train when asking questions...

How did you test it the day before? And how did the mechanic test it? Because engaging 4LO or 4HI (as stated) on dry pavement will kill the transfer case.

Disagreed. Engaging it won't hurt a thing. Driving it a short distance in 4low in a straight line won't hurt a thing either. Even if it does bind-up, it's not going to prevent the low-high shift because as soon as you stop, the t-case clutch goes to minimum duty cycle anyways, releasing any bind-up and freeing up the driveline to perform the shift.

Either way, the transfer case now needs work -- whether thats the motor or the internals of the case itself. Your mechanic should know how to diagnose and fix the transfer case.

As we've found out, this was not the case... the t-case wasn't touched except to unbolt it from the back of the trans. I suspected an electrical gremlin right from the start. Additionally, t-case shift motor failures on second-gens have been surprisingly rare around here. I've read of a lot of people replacing them unnecessarily, and, not surprisingly, it doesn't fix the problem. But a confirmed case of a second gen motor failing is pretty rare.

Got the problem fixed. It was the safety neutral switch. He said that he might of got moisture in it when he cleaned the transmission. Now the explorer starts and 4 lo works like a charm.

That's the way I was leaning... If the GEM doesn't get the signal that the trans is in neutral, it won't even attempt to make the shift. It'll see the switch input, see the brake input, and assume that you're still in gear. Sometimes if the range sensor is right on the edge, you may be able to jiggle the handle and get it to see the signal, but that's not always the case.

The failure to start was the giveaway on this one... Now we've got two symptoms with a potential cause in common. Bingo-bango-baby!!

Glad she's back up and running!

-Joe