Transfer case problem/question

[anders713]

First of all, I am from Denmark, therefor my bad english - sorry

I have a Ford Explorer from 1999. My transfer case *slip* when I activate the 4x4 on dry payment, which is normal. The problem is, that it also does it on muddy or slippy ground, and when i am accelerating, even if I run in the auto mode. Some one told me, that the system in the transfer case, which protect the transfer case from braking when running in 4x4 on dry pavement,
are in some way floppy, and thats the reason it is doing it, when I accelerate or running on normal slippy or muddy ground. He also said, that I could solve some of the problem, by changing the transfer case fluid with some special fluid which contain some special "things". I think he said some kind of coal or carbon stuff. Have anyone heard about that, and can confirm it. If so - which type of transfer case fluid are he talking about?
Thanks in advance, and happy new year to all of you!

/anders

 

[IZwack]

The fluid that person is probably talking about is the "friction modifier" additive. But the transfer case does not require this fluid.

 

[anders713]

The fluid that person is probably talking about is the "friction modifier" additive. But the transfer case does not require this fluid.

OK - Thanks for your reply. Have you heard about the problem with the transfer case?

 

[IZwack]

I dont really understand the description, can you please elaborate on the "slip" you mentioned?

 

[anders713]

I dont really understand the description, can you please elaborate on the "slip" you mentioned?

Well - Bacause i am from Denmark, my english is not the best, but I will try to explain.

The trasfer case is purpose to make a *klunk* or *jump* or *slip* if you are running in 4x4 mode on dry payment, to protect the drive line from braking.
My problem is, that my car-->transfer case is doing this even if I am running in snow og mud, and even if I accelerate.
The system in the transfer case which are there for proceting the driveline are in some way worn, and therefor are protected to good
Is it understandable?

 

[IZwack]

Okay so the transfer case is clunking even in snow or mud. Does the transfer case make the same noise even in AUTO mode (not 4HI or 4LO)?

 

[anders713]

Okay so the transfer case is clunking even in snow or mud. Does the transfer case make the same noise even in AUTO mode (not 4HI or 4LO)?

Yes

 

[IZwack]

The problem might be the rear differential's pinion.

Either way, it sounds like a mechanical problem. I would advise you not to put the vehicle in 4wd on dry pavement. That clunk or noise you hear on dry pavement is not the drivetrain protecting itself from breaking - but rather the drivetrain already breaking as the transfer case's chain is stretched and bearings mounts stressed.

 

[anders713]

The problem might be the rear differential's pinion.

Either way, it sounds like a mechanical problem. I would advise you not to put the vehicle in 4wd on dry pavement. That clunk or noise you hear on dry pavement is not the drivetrain protecting itself from breaking - but rather the drivetrain already breaking as the transfer case's chain is stretched and bearings mounts stressed.

How is it sounds when the drivetrain protecting itself from breaking?
I am able to drive in 4HI or 4LO without any clunk, but as soon as I accelerate a little bit, or it gets a little bit muddy the clunk comes up. When I drive on normal roads in AUTO mode, there is nothing, but if I make a hard accelerate the clunk is there [clunk - clunk - clunk...] - just stop accelerate, and the clunk is gone. It seems to me, that the clunk sound comes when there is a load to the drive line. It is the procting system in the transfer case which is making the clunk sounds.

 

[IZwack]

Okay so first thing I would check is, are the wheel lug nuts and make sure they are tight, then work your way towards the center of the drivetrain from there - so after the lug nuts, check the pinion flange to see if its loose, then the U-joints on the driveshafts, then the flanges on the transfer case.

 

[anders713]

Okay so first thing I would check is, are the wheel lug nuts and make sure they are tight, then work your way towards the center of the drivetrain from there - so after the lug nuts, check the pinion flange to see if its loose, then the U-joints on the driveshafts, then the flanges on the transfer case.

OK - Many thanks for your time

But you don't think it could be the *drivetrain protecting itself system* which are worn or slack in some way. For me it feels like this.

 

[IZwack]

No unfortunately there is no protection in the drivetrain. Putting the vehicle in 4wd on dry pavement is one of the most common mistakes people do.

 

[anders713]

No unfortunately there is no protection in the drivetrain. Putting the vehicle in 4wd on dry pavement is one of the most common mistakes people do.

I think you misunderstand me, do to my bad english. Let me try to ask in an other way

What will happend if I drive in 4wd on dry pavement? Normally you will hear some clunk sounds, because some systems is slipping to provent any damage do to heavy load - right?

In my manual at page 158 the following text is found:

--
The vehicle should not be operated in 4WD HIGH and 4WD LOW
on dry or merely wet pavement. Doing so will produce excessive
noise, increase tire wear and may damage driveline components.
These modes are intended for use only on consistently slippery or
loose surfaces.
--

What is makeing the excessive noice if driving on dry pavement?

 

[IZwack]

Sorry for the misunderstanding.

What will happend if I drive in 4wd on dry pavement? Normally you will hear some clunk sounds, because some systems is slipping to provent any damage do to heavy load - right?

What would happen is that the chain in the transfer case is stretched until two of the four tire slides against the pavement. Along with the chain stretching, the bearing lobes in the transfer cases are also elongiated because the transfer case housing is made from fairly soft metal (typically aluminum or magnesium). When these tires slide, tension in the system is relieved. The system itself is not slipping, what is slipping are the tires against the pavement, the system remains tight. As I said, engaging 4wd on dry pavement is one of the most common mistakes people make and it often leads to trouble in the future.

What is makeing the excessive noice if driving on dry pavement?

That could be anything, its difficult to pinpoint exactly whats causing the noise over the Internet. It could even be one of the bearing lobes I mentioned earlier -- which might be detecable by up-down or side-side movement on one of the transfer case's output flange.

 

[anders713]

That could be anything, its difficult to pinpoint exactly whats causing the noise over the Internet. It could even be one of the bearing lobes I mentioned earlier.

OK - Thanks again for your professional help. I greatly appreciate it

Some chap told me that the transfer case had some kind of a drivetrain protecting system, but he had obvious not the right expertise.