98 Navigator will not engage 4X4 front axle

bhickmott

Registered
Hi Guys

Any suggestions for my 98 Navigator that will not engage the front axle for 4 wheel drive in either A4WD, 4X4 or Low Range ?

The diaphram unit on the front axle works fine. If you connect vacuum to either side of the diaphram it will engage or disengage the the 4 front axle correctly. The problem is that vacuum does not shut off and is always applied to the disengage side of the diaphram. Traced the vacuum lines back to two electrically controlled vacuum solenoids on the firewall and found that 12 volts is always applied to the disengage solenoid regardless of where the switch on the dash is positioned (2WD, A4WD, 4X4, Low). The lights on the dash do change properly and you can hear relays clicking as you move the dash switch, but the disengage solenoid always receives 12 volts.

Does the power for the solenoids come directly from the Generic Electronic Module (GEM) ? Is there an easy way to diagnose ? Does anyone make a cheap replacement module ?

Bill Hickmott
617 803 4104
 
RE: 98 Navigator will not engage 4X4 front axle

Hmm. wish i could help.

My 02 doesn't even have a 2wd mode. I don't believe the front axle will disengage at all on mine.

the cheap fix is to switch the vacuum lines on the diaphragm and drive around in A4wd all the time. Assuming your truck still has the clutch setup in the transfer case like mine.
 
RE: 98 Navigator will not engage 4X4 front axle

We have had these systems on some of our F-series in our fleet and usually it is a vacuum problem. Your scenario sounds different since you say you always have vacuum on the disengage side of the control actuator.

I believe the solenoid will have power all the time and the ground is switched? Test for continuity to ground while operating the switch.

An EVTM would be nice. I tried my tired DVD manual and it still refuses to work.
 
RE: 98 Navigator will not engage 4X4 front axle

Yeah .... I had already planned that was my fall-back solution once the snow comes. Yes, the 98 does have the same transfer case clutch set up for A4WD so that the 4X4 is switched in as needed. The downside is that I will loose gas mileage with axles engaged all the time. Too bad they eliminated the 2WD mode on the 02 !

Bill
 
RE: 98 Navigator will not engage 4X4 front axle

Thanks Driller ... I'll try that tomorrow. It could be that the solenoid is stuck always open. I did not check to see if it switches vacuum on & off with 12 volts applied and disconnected directly.
 
RE: 98 Navigator will not engage 4X4 front axle

Problem turned out to be a defective vacuum solenoid. There are 2 solenoids mounted a common bracket on the firewall to the left of the power distribution area and right behind the battery. The right solenoid (E8AE-9H465-AA) controls the vacuum to the return side of axle engagement diaphram. The left solenoid (E8AE-9H465-BA) controls the vacuum to the activation side of the axle engagement diaphram. The right solenoid was stuck in the open position which allowed full vacuum to the return side of diaphram at all times. I took it out and applied WD40 with 100 psi of air coupled with a few good "raps" on the bench and it did begin to function again, but it still had a slight leak in the off position. The 4X4 now works fine even with the slight leak, but I have ordered a replacement solenoid ($44.00) to be sure.
 
RE: 98 Navigator will not engage 4X4 front axle

Where are you ordering your parts from? Did they tell you about the parts changeups?

Ford has been having chronic problems with water entry into these solenoids, corroding them from the inside and seizing them,as you've seen!

They've been redesigned and those old part numbers (E8AE-9H465-AA/BA) have been superseded.

The latest designs are listed as:
6L3Z-9H465-A (identified by electrical connector rib at 9:00 position)
6L3Z-9H465-B (connector rib at 6:00 position).

The original part numbers are still available, but if you don't want this problem re-occurring, you DO want these new solenoids.
 
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