Tranny or Transfer case?

[thethirdmurph]

ok so my 4wd was acting up so I rebuilt the transfer case motor.. put everything back together and went to advance auto to replace the fuse.. Well fuses continued popping..So I got back in the truck and was leaving Advance, so I thought, no reverse.. no forward. However when I put it in drive the speedo takes off as if I were driving.. if I put it straight from drive to park it chatters just like it would if I were driving.

at first it seemed obvious to me that it was the transfer case but I was talking with a buddy who is a master tech at a ford garage and he mentioned seeing the spline on the shaft going from the tranny to the transfer case was rotted..

I couldn't find anything about this in the threads but have you guys heard of anything like this??

 

[IZwack]

The transfer case is in Neutral -- due to the shift motor being misaligned or you didnt rebuild it properly -- and is now pointing between LO and HI range (where the neutral point is, although its often not labelled).

The grinding sound you hear is probably this gear chipping its tooth away

 

[thethirdmurph]

I noticed when replacing the motor that the transfer case was labeled with an "H" "N" and a "L" I figured "N" was 4X4auto

 

[IZwack]

Oh good so it is labeled.

No "N" is not 4x4auto. "N" is no movement at all.

The transfer case must go through "N" when it goes from "H" to "L" -- that is the reason why your vehicle should be in Nuetral so it can move the transmissions output shaft just a hair in order to engage the planetary gears properly.

 

[thethirdmurph]

if hi is full time hi. Where does it go to engage in auto?

 

[IZwack]

The transfer case is in "H" mode when the vehicle is in 4Auto mode.

See the transfer case motor doesnt move when it engages 4WD - because 4wd engagement is done through an electromagnetic clutch inside the tranfer case. Therefore, the shift motor will only move you want to go from HI to LO.

This is why you can switch between AUTO and HI while the vehicle is moving -- because there is no gear change, its all in the electromagnetic clutch. You do however have to be stopped when going between HI and LO because there is a gear change.

My half-fast job of rendering what the electromagnetic clutch looks like (ignore the name and the numbers):

 

[thethirdmurph]

thanks for the explanation...so does that mean I should be able to shift from 4auto to 4hi without the transfer motor?

 

[IZwack]

yes, thats right but there are some wires (speed sensor aaaand electromagnetic wire) that are bundled with the wires for the shift motor. Also, if you remove the shift motor, fluid will be coming out of that center hole. And technically there will be nothing holding the transfer case's shift fork from shifting between LO and HI -- and even Neutral.

 

[thethirdmurph]

so if my 4X4 hi isn't working it doesn't really have anything to do with my transfer motor being locked up

 

[IZwack]

Thats right!

 

[thethirdmurph]

why might the 4hi not be working ?? BTW Thanks for letting me pick your brain you've been a tremendous help!!

 

[IZwack]

4HI is most of the time an electrical issue, I think I mentioned this in your other thread, but check the brown wire with a voltmeter.

 

[thethirdmurph]

I didn't totally understand what you were saying in the other thread . however after having it all apart and seeing that "N" actually means neutral now I sort of understand :biggthump: . I'll check that brown wire in a min.

I'm also having a fuse issue with the motor. the motor spins great until it is grounded against the transfer case.. There was no strain on the motor either. I only bolted the bottom bolt and let it hang. if I let it hang without bolting it up it runs back and forth perfect.

 

[gijoecam]

so if my 4X4 hi isn't working it doesn't really have anything to do with my transfer motor being locked up

Ding Ding Ding!! We have a winner!

The transfer case motor is not responsible for the transfer case locking. It simply controls the positioning of the low range gear-set. Lockup is handled by the transfer case clutch coil (great rendering, by the way!!), which is ultimately controlled by the 4wd control module in your truck.

-Joe

 

[thethirdmurph]

alright so I got the motor working, and it will go into low..however the brown wire is only getting like 3.6 volts. so my question is where does that brown wire come from?? is there a relay that could be going out?

 

[gijoecam]

At idle in 4auto, that's normal. The system modulates the duty cycle of the transfer case clutch coil. If you have any power at all to the clutch coil, it's getting juice. Once you start moving, you'd see the voltage jump to roughly 14.

Let's begin at the beginning: What's 'acting up' on the 4wd system?

 

[thethirdmurph]

well my 4hi light isn't coming on

 

[thethirdmurph]

4X4 high light flashing. I just checked it again I'm getting 3.8 volts on the brown wire in every setting, 4hi 4lo and 4auto.. it never changes:scratch:

 

[gijoecam]

4X4 high light flashing. I just checked it again I'm getting 3.8 volts on the brown wire in every setting, 4hi 4lo and 4auto.. it never changes:scratch:

When stopped, that is normal. The system operates at a minimum duty cycle, resulting in the reduced voltage. As I already stated, that's normal.

If the light is flashing, that means the system has detected a fault and stored a trouble code. We can guess over and over again as to what *might* be the issue, but the only way to know for sure is to have the codes scanned. AutoZone will not be able to do it as those codes are stored in a different part of the system. Any Ford dealer and some better independent shops will have the WDS or NGS systems necessary to scan those codes.

Now, that being said, look for any obvious signs of trouble: Chafed wires on the rear diff speed sensor, or the front two ABS sensors would be the place I'd start. Aside from that, your guess is as good as mine. Without the code, once can only guess.

-Joe

 

[thethirdmurph]

I tried sending 12 volts down the brown wire from the cigarette lighter like you said in another thread and it still didn't seem to kick in.