3rd gen 4x4 center diff question

[Ocean Pacific]

I'm trying to better understand how the center diff works in my 03 4x4. would it be considered locked or open when engaged? Does it distribute power 50/50? I think I'm correct in saying that 4H and 4L gears are always meshed to the drive train and the shift motor just selects between the two? Thanks for your help!

 

[Ronin8002]

I'm trying to better understand how the center diff works in my 03 4x4. would it be considered locked or open when engaged? Does it distribute power 50/50? I think I'm correct in saying that 4H and 4L gears are always meshed to the drive train and the shift motor just selects between the two? Thanks for your help!

If you have 4x4 (not AWD) then you have a transfer case, not a center diff.

When in 4x4 auto, you have 5% power in the front and 95% in the back. If the system detects slip in the rear wheels (by comparing driveshaft speeds), it incrementally adds power to the front until the rear wheels stop slipping and then it goes back down to 5%. In 4-hi and 4-lo its 50/50.

I Posted a link below on how it works.

EDIT: Fixed the percentage of power numbers

 

[Ronin8002]

Here's a good link that gets into pretty good detail on how it actually works:

http://www.rsgear.com/technical/articles/2008_05.pdf

 

[Ocean Pacific]

Thanks for the link, that really helped. I do have one more question. If you have the 3.73 gears in the rear, the front would also need 3.73. Correct?

 

[Ronin8002]

Yes, both the gear ratios must be the same. It's also very important that the tires are the same size and are inflated to the same pressure.

 

[BigRondo]

Yes, both the gear ratios must be the same. It's also very important that the tires are the same size and are inflated to the same pressure.

Not trying to be the bad guy here but, the tires should be inflated according to the sticker inside the driver's door. My '02 states 35 PSI in the rear tires and 30 PSI in the front tires.

 

[Ronin8002]

Good catch BR.

 

[my pos mounty]

Not trying to be the bad guy here but, the tires should be inflated according to the sticker inside the driver's door.

Since the "Explorer rollover" controversy, and its underlying cause, I don't put too much stock on those stickers.
The found that they were caused by under-inflated tires, but they were inflated to what that sticker stated as the recommended pressures.
I believe that Ford, as part of a TSB or a recall, placed "replacement" stickers over the incorrect entries.

 

[BigRondo]

Good to know. How do I know if my sticker is correct or needs the TSB sticker?

 

[my pos mounty]

That incident took place prior to the third gen's creation. (recalled in May of 2000)
Your safe.

 

[BigRondo]

Thought so but wasn't sure. Thanks for your help.