4x4 high

[Midnightride42]

This is on a 97 F150 4x4 extended cap with the 4.6 V8. Has 108k miles on it. Anyways, I just got the truck. When you switch it to 4H you can hear clicking in the dash, but no light turns on in the dash. If I put it in neutral and put it in 4L, you can hear the clicking in the dash and the light turns on. Occasionally the light will come on for a second for hte 4H but then goes right off. Suggestion on what to check or could be causing this. My thought was it's something electrical. I haven't taken it off road yet to see if the 4H actually is engaged or if it's just a light no coming on. Figured I'd check on here first.

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[Bindernut]

I'd suspect the electric shift motor...or actually just the position feedback switch that is mounted on the back of it. Sounds like it is actually shifting since it will go into 4lo, but in the 4hi position I would suspect that the switch contact for the 4hi position is not quite right.

I would try a different shift motor.

[Midnightride42]

since i'm new to this....can you point me in the right direction to where it's located? Picture perhaps.

Is there a way to test it, or fix it?

I had the window down last night and in my drive way I can actually hear 4L engage outside but when putting it in 4H noting happens outside only the clicking noice in the dash.

Thanks,

[Bindernut]

I don't have any diagrams handy on my computer, but the electric shift motor is bolted onto the back of the transfer case.
Here's a link I found on Google...looks like the same diagram as the factory service manual. The motor is shown as part #72.
http://www.drivetrain.com/bw4406tran...#Illsustration
I don't have a wiring diagram for this circuit on my '97 either...I need to copy that from the service manual next time I borrow one.

On my truck, I can't hear the shift motor run when doing the 2hi-->4hi shift or back either. Only thing I can hear is the solenoids on the engine firewall that engage the front hubs clicking during that shift. When shifting to 4lo and back, I can hear the clunk as the low-range gearset is shifted in quite well though.

You can try shifting the switch from 2hi to 4hi, then unbolt the shift motor (3 10mm head bolts) from the transfer case and check what position the shifting cam shaft is in (it's part #77 in the above diagram). This shaft has a kind of keyed end that looks like an arrowhead so it can only go back on one way. The transfer case has marking on it for 2hi, 4hi, 4lo that the arrow points to when it is shifted into each position.

On the rear of the shift motor assembly, there is a blue plastic plate plate with several wires...this is the position feedback switch I mentioned. I don't believe that's a separately serviceable part, it's replaced with the whole shift motor as an assembly.
It's possible that you've also got a damaged wire from the 4hi contact on that switch or possibly a bad shifting switch on the dash too...I've personally never seen that switch go bad, but I suppose it is possible. I would suspect that it is working though since you can shift into 4lo.

Hope this helps!

[Midnightride42]

I'll look over those parts mentiond.

One question I have now.....I was doing a search and I read some F150 use vacum lines to engage the 4x4 low or high.......do the 97 use the same setup or is that on other F150?

I wasn't sure if perhaps there are seperate lines one that controlls high and one that controls low. and maybe that's what is not working.

Perhaps the 4x4 high is engaging but the light is off? Specially since you mentioned you can not hear yours engaging when putting in 4H.

I'll look at it tonight or tomorrow.

Thanks,

[Bindernut]

On the 97-03 F150, Ford uses vacuum lines to lock/unlock the front axle shafts, but the transfer case itself (2hi, 4hi, 4lo selection) is shifted with the electric motor on the back of the transfer case.

The solenoids that operate the front axle are located under the hood on the firewall towards the passenger side of the truck. There are two...one to engage the front axle and the other to disengage it.


On that switch mounted on the shift motor, here's how the various contacts are switched when the transfer case is in the listed range. Each contact should be labeled A through D.
Closed means that that contact is grounded, and open means no connection to ground. You can check these with an ohmmeter.

When in 2hi...
A = closed
B = open
C = closed
D = closed

4hi...
A = open
B = closed
C = closed
D = open

4lo...
A = open
B = closed
C = open
D = closed