I have a 1997 4.2liter V6 F-150 with a manual tansmission, and 4 wheel drive. I don't use the 4 wheel drive much, but when I put the lever into 4 wheel drive recently, the light didn't come on on my dash. I also did not have 4x4, and I got stuck. I kept trying to move the floor shifter in and out of 4H, 4L, and so on, and it finally worked and I got out. Unfortunately, it hasn't worked since. I do feel the transfer case working when I put the shifter into 4x4, especially in 4L, but the dash light does not come on, and I don't think the front wheels are pulling. Does anyone have any information on where to start? I checked underneath the truck, and noticed a leak in the transfer case at the rear, where the driveshaft bolts up. I plan to get a new gasket and fix this. Any ideas or help would be much appreciated.

Thanks,
Steve
si83gt@verizon.net

 

Try looking at your vaccum lines going to your shifter motor on the front axle. You have two selonoids on the passenger side firewall that activate the lines...check those also. Locate these items do a couple of checks and go from there.

 

I am assuming I should look to make sure the vacum lines aren't cracked or leaking. But what do I check on the solenoids? Is there a voltage check I should do? What should the readings be, and how should I go about it?

 

Yeah you need to look for cracks or leaks on your lines. But one easy way to elimenate alot of tracing out lines is to use a vaccum tester. First test at the shift motor, take one line at a time and lock in the 4x4 and take it out, nly one line will have vaccum at a time. It should pull around 20 lbs vaccum. If you don't get any pull at the shift motor, hook up at the selonoids, they activate vaccum when the 4x4 is locked in and when its not, one does one or the other. If there is vaccum at the selonoid, you have broke lines, if not, you could have a connection problem to the selonoid or a bad selonoid. Go from ther and see what you get. And if I'm not mistaking, I think the blue line is the line to lock in the 4x4, and the pink takes it out. Good luck.

 

I forgot to mention this in one of your other posts, but unless you're someplace well below sea level, it's not possible to pull 20 psi of vacuum anywhere on this planet. Max vacuum anywhere on the surface of the Earth is 14.7 psi (atmospheric pressure).

Also, he doesn't have a shift motor, he has a manual transfer case. They're wired completely different, but still rely on the GEM to activate the center axle disconnect and its vacuum solenoids. Because he's not getting a light, it leads me to believe that the GEM isn't getting the signal that the transfer case is in 4wd either. If the GEM doesn't know the t-case is in 4wd, it doesn't know to lock the front axle either. Sooo....

Start with the basics: Check the fuses:
Power Distribution Box:
Fuse #17 (30A)
Fuse/Relay Panel under the dash:
Fuse 23 (10A)

Second, unplug the connector from the transfer case and check for a ground signal through the transfer case on the LB/BK wire in 4high and the GY wire in 4low.

Check for 12V at both of the vacuum solenoids on the firewall. One or the other should have a ground signal back through the GEM at all times as well. Never both.

It really sounds like either a transfer case wiring problem or a GEM problem. I've got my money on a fuse as they both have the #23 fuse in common.

JMC should be along shortly to confirm it.

-Joe

If the light isn't coming on, it's

 

O.K., I will look for those things, thank you very much for the info!!!! Risking sounding like an idiot, I have to ask another question. What is the GEM? Where do I find it?

 

Check both fuses. If they check out then unplug the switch on the T-case and look for corrosion or broken connector. If that checks out, ground the gray wire. The 4x4 light should come on. If it does, replace the switch. If it doesn't turn on then this will get interesting. Let us know.

JMC

 

I also have a manual transfer case, but the front end still locks in by a vaccum actuator, and every book and manual I have looked at calls it a shift motor regardless if its electronic or vaccum. Also, I just went outside, and I guess my gauge is wrong, but once again I pulled 18.5 lbs of vaccumon my line locking in the 4 wheel drive. I was just giving the best info I had available, his truck could be different, But that was a good starting point.

 

O.K., I checked the switch on the transfer case, and grounded both sides of the switch. The grey wire made the 4x4 Low light come on, and the other side made the 4x4 light come on. They both came on with the ignition switch in the on poisition. So I would say that switch is bad. What is the name of that switch, and can I get a replacement at any auto store or do I need to visit a dealer? Thank you very much for your help!!!!!!!!!!!!!!!!!!

 

It is called a (4WD) Four Wheel Drive indicator switch (manual transfer case). If they need it it is a BW 44-06 transfer case.

JMC

 

Is that the same as a Four Wheel Drive Selector Switch? Or a Four Wheel Drive Actuator switch? I just want to make sure I am getting the correct thing. As you can tell, I am not very familiar with four wheel drive. But if you need to get a Mustang to run a 1/4 mile in 10 seconds, I can help you out with that.

 

The 4wd selector switch is the rotary switch in the cab. If you tell them it is the switch on the manual transfer case they should get you the correct one.

JMC

 

[QUOTE=GIJoeCam]I forgot to mention this in one of your other posts, but unless you're someplace well below sea level, it's not possible to pull 20 psi of vacuum anywhere on this planet. Max vacuum anywhere on the surface of the Earth is 14.7 psi (atmospheric pressure).

I meant to say around 20 -Hg or around I think 7 to 8 psi. My apology, redneck mistake.

 

Aaaah, there we go.... It helps if you use the correct units LOL!!! 20 inches of mercury is about 9.8 psi. A complete vacuum anywhere on the surface of the Earth is 29.9 inches of mercury, 760 mm Hg, 14.7psi, 1 atm, 1.01 bar, 101325 newtons per square meter, or 406 inches of water.

Useless info, I know.....

Back to the topic at hand,

Yes, the indicator switch is what you want. It's possible that you may be able to fix the old one. JMC, correct me if I'm wrong, but it bolts to the side of the t-case where the shaft passes through it, correct? Doesn't the switch plate take the place of the shift motor?

And yes, technically the center-axle disconnect could be considered a vacuum motor. However, when talking about the 4wd systems, the term 'shift motor' is generally used to refer to the motor that mounts to the side of the transfer case and turns the shift rod to lock the transfer case and engage low range.

-Joe

 

Joe,

The switch is on the front of the T-case just below the breaher barb. It is screwed into the T-case and it is ligned up so that shift rail pushes on the switch. As the rail is moved through the different positions the switch contacts are moved accordingly.

JMC

PS. The Electric T-case has the boss for this switch but it is not drilled. The Manual t-case has the boss on the rear half for the electric motor but it is not machined.