Does my transfer case have a chain? (1999 Eddie Bauer)

[TheFlyingFord]

Howdy, I'll get right to the question here: Does my transfer case have a chain inside it? I know it sounds silly to ask, but I'm not too familiar with Ford transfer cases, and I've had trouble trying finding any schematics of them.

The issues I've been trying to fix are two things: The 4wd kept turning off randomly, which led to a couple butt-clenching moments while driving in deep snow last winter. The second issue is that *something* has started grinding and binding up bad when I turn. It got so bad that I removed the front driveshaft, which temporarily fixed it. This led me to believe the chain inside the transfer case had stretched. Ultimately, I'd love a second opinion before I spend half a day (or more) removing the transfer case to find it has no chain and that's not the issue. xD

Here's what I know about the truck:
It's a 1999 Eddie Bauer.
The differential locks are not vacuum actuated.
The 4x4 is electronically actuated; no vacuums.
There is a loud grinding sound when I turn, and the wheels bind up.
I removed the front driveshaft, and the grinding stopped.
My 4wd light is flashing on the dash.
I changed the transfer case shift motor around a year ago. (An early attempt at fixing the first issue.)
The dashboard 4wd actuator switch is new. (Also an early attempt at fixing the first issue.)
The dashboard actuator switch symbols are for AWD, 4 high, and 4 low. (Not sure if this helps any.)
All fuses related to the 4x4 system have been checked and are good.

Here's what I do NOT know about the truck:
I am not sure if the transfer case has a chain (obviously).
I'm not sure the model or brand of the transfer case.
I'm not sure what month the truck was built in 1999. (Not sure if this is important.)


If y'all need any more info or have any more questions, I can try to provide them. Any responses are greatly appreciated!

Thanks! -Z

 

[joethefordguy]

"...I removed the front driveshaft, which temporarily fixed it."
so you're saying it started grinding, etc. again after a short while without the front shaft; even with the shaft removed?

 

[WEDGE]

I wouldn't think it has "differential locks" unless installed aftermarket.

 

[TheFlyingFord]

"...I removed the front driveshaft, which temporarily fixed it."
so you're saying it started grinding, etc. again after a short while without the front shaft; even with the shaft removed?

Sorry, I wrote that a bit confusing. It stopped the grinding completely and it hasn't showed up since. The "temporarily" thing was because removing the front driveshaft is a temporary thing to do. I'd like to fix it right ideally.

 

[Yupster Dog]

Sorry, I wrote that a bit confusing.

I agree except all confusing.

Best take to a shop to get fixed right ideally.

 

[joethefordguy]

Sorry, I wrote that a bit confusing. It stopped the grinding completely and it hasn't showed up since. The "temporarily" thing was because removing the front driveshaft is a temporary thing to do. I'd like to fix it right ideally.

I'm sorry, I'm still confused.
you removed the driveshaft, and the problem went away.

did you put the driveshaft back, and the problem was still gone? or is the driveshaft still out, but you intend to put it back and believe the problem will reoccur?

 

[TheFlyingFord]

I'm sorry, I'm still confused.
you removed the driveshaft, and the problem went away.

did you put the driveshaft back, and the problem was still gone? or is the driveshaft still out, but you intend to put it back and believe the problem will reoccur?

I put the driveshaft back on a few months ago, and the issue was still there. I took it out again because we needed to drive it still.

 

[TheFlyingFord]

I agree except all confusing.

Best take to a shop to get fixed right ideally.

I don't trust the mechanics in my area. I have the skill to fix it right, I'd just like a second opinion on the transfer case chain before I spend a day taking out the transfer case. That's a lot of work for possibly nothing.

 

[Plati]

Howdy, I'll get right to the question here: Does my transfer case have a chain inside it? I know it sounds silly to ask, but I'm not too familiar with Ford transfer cases, and I've had trouble trying finding any schematics of them.

The issues I've been trying to fix are two things: The 4wd kept turning off randomly, which led to a couple butt-clenching moments while driving in deep snow last winter. The second issue is that *something* has started grinding and binding up bad when I turn. It got so bad that I removed the front driveshaft, which temporarily fixed it. This led me to believe the chain inside the transfer case had stretched. Ultimately, I'd love a second opinion before I spend half a day (or more) removing the transfer case to find it has no chain and that's not the issue. xD

Here's what I know about the truck:
It's a 1999 Eddie Bauer.
The differential locks are not vacuum actuated.
The 4x4 is electronically actuated; no vacuums.
There is a loud grinding sound when I turn, and the wheels bind up.
I removed the front driveshaft, and the grinding stopped.
My 4wd light is flashing on the dash.
I changed the transfer case shift motor around a year ago. (An early attempt at fixing the first issue.)
The dashboard 4wd actuator switch is new. (Also an early attempt at fixing the first issue.)
The dashboard actuator switch symbols are for AWD, 4 high, and 4 low. (Not sure if this helps any.)
All fuses related to the 4x4 system have been checked and are good.

Here's what I do NOT know about the truck:
I am not sure if the transfer case has a chain (obviously).
I'm not sure the model or brand of the transfer case.
I'm not sure what month the truck was built in 1999. (Not sure if this is important.)


If y'all need any more info or have any more questions, I can try to provide them. Any responses are greatly appreciated!

Thanks! -Z

Yes it does have a chain -->
But I can't quite get why you've focused in on that. Does your year have IWE?
Not saying thats it but seems more likely than the chain thing. Course, I dunno.

this might help maybe somewhat possibly
https://www.expeditionforum.com/threads/1999-4x4-solenoid.27435/

 

[joethefordguy]

I put the driveshaft back on a few months ago, and the issue was still there. I took it out again because we needed to drive it still.

ok, finally, I get it. sorry.

FWIW, my 04 Expy 4x4 has the BW4416 transfer case and it is chain driven. once you find out which transfer you have, you can find out whether it's a chain or gear drive.
the VIN is where I'd start looking for the transfer case model.

 

[joethefordguy]

FWIW, from Wikipedia:

"
First generation (1997–2002) First generation (UN93)
...
Transfer case (4x4 models)
2-speed BorgWarner 4406
High range ratio: 1.00:1
Low range ratio: 2.64:1
... Expedition was available with automatic full-time ControlTrac four-wheel drive with two-speed dual range BorgWarner 4406 transfer case and a center multi-disc differential. ControlTrac was introduced in 1995 and included four selectable modes: Two High, Auto, Four High (lock) and Four Low (lock). Two High mode and Auto mode with auto-lock was not available."

as you can see, on this and many other sites on the internet (https://schematron.org/borg-warner-4406-transfer-case-diagram.html), your transfer case is a chain drive.

 

[Frank Swygert]

If you removed the front driveshaft and the issue stopped, it might be the shaft. Inspect the u-joints, or just replace them (they aren't expensive). Do you have the ControlTrac or standard 4x4? The sound is more likely in the controls, or if it uses an axle interlock with a servo motor on the axle to lock 4WD in it may be that. The vacuum servo on those can get weak or have a leak in the diaphragm or tubing (check the tubing first!) and grind when trying to lock in. If it has vacuum actuation I'd go ahead and just replace ALL the vacuum lines associated with 4WD first. The lines are old, and may just not be sealing well on the nipples any more, or have cracks if they use the hard plastic line instead of rubber tubing (most 90s and up vehicles do).