Transfer Case Issue

[Gerald S]

First of all, let me say that I have used the information on this site to fix a lot of problems on my Explorer. Thanks to all of you guys for the information.

I have a 96 Explorer that I use for offroading. Here is a picture:

I have 31inch tires on factory rims, no lift or TT at this time, a winch and bumper.

The problem that I have ran into revolves around my transfer case. It works, but not like it was designed to do. I should be able to switch it to 4Auto while moving, have the indicator light come on, and when the rear starts spinning, then it should engage the front axle as needed. It will no longer do this. When I shift to 4Auto, the indicator lamp will not come on until I come to a complete stop. Then the transfer case engages and the light comes on. When I say that the transfer case engages I mean that it directly connects to the front axle and works just like a fully engaged transfer case on a part time, manual transfer case (think Brown wire mod without me doing the Brown wire mod). Any idea why this may have started to happen? 4 Low works just like it is supposed to.

I have swapped out the Gem Module for one out of another Explorer of the same year and options that had no problems and worked the 4x4 sytem just fine (the donor vehicle), but it did not fix my problem.

As a side note, I do have a small vacum leak that I am chasing down as well. The only symtoms that I have experienced are: 1. a change in the HVAC system when it defaults to the defrost setting (above 35 mph), regardless of where the switch is set to and 2. when traveling above 35 mph in 4Auto, the front axle loses enough vacum that it disengages and kicks the system out of 4 wheel drive.

I have tried using the Search funtion, but I have not found any information relating to my problem.

 

[Turdle]

OK both problems are related

Look in the passenger front wheel well area behind the bumper for a black grapefruit sized ball. This is the vacuum reservoir.

The hard lines go toward the truck along the inner fender liner, and often get broken from tires or melted from the exhaust if the lines get get loosened from the retainers, or hit by larger tires--

This vacuum "powers" the vent functions in the hvac, and the " center lock differential" up front in your 96 ( 95 4wd also has this)

Look for the red line going from the ball to your front diff, and a grey line running to the coolant bypass valve.

This thread may help you
http://www.explorerforum.com/forums/showthread.php?t=192842&highlight=defrost+vent

 

[Gerald S]

Thanks for the reply. I have already checked all of the lines mentioned in that thread that you gave me and found no problems. I also went ahead and replaced my vacum resevior with a new one from Ford, but nothing helped. The engine runs fine at all rpms with no idling promblems. I have tried spraying carb cleaner, wd40, and even propane at all of the lines and connections, but have not a found the problem yet.

I know that the vacum problem is causing my axle to disconnect itself once the vacum gets low. I also figured that the low vacum is the reason that I have to stop to get the system to engage when I turn the switch. But what I can't figure is why the transfer case is suddenly acting like it is a true part-time unit instead of an auto/swithching unit. I am not sure if both of these problems started at the same time though. Any other thoughts or suggestions?

 

[snoranger]

First off, a smoke test is the best way to find the vacuum leak. Find someplace with a smoke machine. Simple explanation: They pump low pressure smoke into the intake and it comes out wherever there is a vacuum leak. (not sure where you are, but if youre close, I have one.)

As far as the 4WD isuue: Check your wheel speed sensors and the T.O.D. relay.