Ok I have read through SEVERAL internet posts About transfer case problems. However no specific post for this particular issue.
99 nav/5.4/auto/awd,4h,4l/153k miles

1.) shift motor failed about 2 yrs ago. No dash 4x4 lights.
2.) never used 4x4 h or l. Since broken.
3.) last week replaced shift motor (rebuilt) black cover not gray cover model.
Original was blue cover.
***this may be the problem, need clarification.
Would not using the gray cover shift motor cause awd binding to occur?
Would a defective rebuilt part cause the awd binding.
4.) installed new GEM module as well.
5.) no gem codes on old gem no new codes on new gem.
6.) once both parts were installed the following occurred:
A.the 4x4 dash lights come when ignition starts.
B.shift from awd to 4x4 H the 4x4 dash light comes on.
C.shift to 4x4 L foot on brake,neutral,stopped. Dash light for 4x4L comes on.
***note when in 4x4 H&L on dry pavement there is binding when making sharp turns, it my understanding this normal.
D.shift back to AWD and the binding is still present on sharp turns.
E.unplugged the shift motor connector at the shift motor and the binding disappears.
F.also had the transfer case fluid changed.
I have found NO solutions on any google searches for this particular problem.

Is it the transfer case shift motor? Either defective or not the upgraded unit
Is it the transfer case unit "magnetic clutches" or mechanical damage to the gears.
Is it the 4x4 relay
Is it the "tods relay"
Or none of the above?
Please advise. Buy another shift transfer motor, the gray case one,
Buy new t/c sensors.
Add an additive to the t/c fluid.
The tires are all new. They are all larger in circumference than the originals 265/r70/17 though.
Could it be the rear differential fluid and front end fluid as well.
I sure would like to have a solid answer to this and be able to share with others who are struggling with this same issue.
Thanks in advance. Jmmranger

 

Go into the power box under the hood and remove fuse #104. When in AWD, does the binding stop with the fuse out?

 

Ok- unplugging the transfer case shift motor connector, would be the same thing.
When the electrical power to the transfer case shift motor is removed the front end does NOT bind in AWD.
When power is supplied to the transfer case shift motor again the binding occurs again.

 

Alrighty then, since you have all the answers you don't really need us. Good luck with your repair.

 

Wow! That really wasn't the type of response I was looking for with regard to this matter. ALL responses are welcome!!!. I have done a lot of research into this matter and I am looking for clear concise answer so we can make sticky for this matter. These responses show up on google years after input.
I may repost if I don't get anymore responses. Where are all the experts?

 

You just insulted one of them.

 

Let's back on track to resolving this issue. OK-Downloaded three pics to my album page of schematics for 1999 navigator- related to transfer case. not sure how to provide a link though. Any help?

 

OK- Had a clear day and the truck available- As you requested I reconnected the shift motor connector. Then removed the #104 30A fuse from the hood fuse box.
Started the truck and drove around making sharp slow turns and no binding was found.
The 4H dash light did not activate when moving the dash switch to 4H. When restarted the 4x4 and 4lo dash lights activate upon startup and then shut off.

What next?
Thanks in advance. jmmranger

 

In that case the shift motor and the front clutch are okay. The most likely culprit is the speed sensor on the front of the t-case. The lack of a signal from the front sensor gives the A4WD module the impression that the front axle is stationary while the rear one is not.

 

Thanks! I will go to the dealer and have get both of the transfer case speed sensors replaced.

What about replacing the transfer case fluid with "Chatter-Free Fluid" Will this add longevity to the Transfer Case Clutches?

 

In my personal experience I have alway found it best to stick with what the manufacturer recommends. To me the clutch should never chatter unless there is a problem. In such a case, the chatter free fluid is only masking a problem that will leave you stranded at the most inopportune time.

 

I have had this same problem with my 99 Navigator for the last couple months where I'm making low speed turns into a parking space, it would "hop" as if the 4x4 was engaging..but not do so if I slowed down even further when turning. I recently took the Nav into a Ford dealer to have the brakes done and to see if they can diagnose it. The ABS light has been on ever since I bought the NAV but everything worked fine..so I left it for another day untill they said the hopping would be cured by replacing the ABS sensor...hmmmm...wrong! Somehow whatever they did then started affecting driving going straight, binding while starting from a stop going forward straight sporadically. Once I read this post, I went to the garage, pulled the #104 fuse and took off for a ride..wallah!...no more. As I understand it I will need to either 1) leave it as it is until I drive it into the ground or 2) get the speed sensor replaced correct? Is there more than one to replace and can a lowly guy like myself with a little bit of wrenching experience accomplish that replacement or take it into the shop?

Thanks ahead of time for your assistance. What a great forum!

 

1) If you wish.
2) Yes

There is a speed sensor on the front and on the back of the transfer case, next to the driveshafts.

 

I have had the front drive line out of my Expedition for about a year because the binding/popping in the front end was pretty severe. I recently reinstalled the driveline to trouble shoot the issue. I removed the 104 fuse and the binding remained the same. Any further guidance on trouble shooting the shift motor or front clutch would be appreciated!

 

I have a 99 espy that started binding and making noise when I turned sharp. I had to replace my cv axles in the front end. That fixed it and she was like new again. They were only $60 per side at auto zone