front diff operation

[ddgts68]

Can someone explain/ point me to a video on how the front diff works on 99 xlt 5'4l 4wd? I did a search only find how to change fluid. I have the Haynes/ Chilton ( I don't remember which) manual and It explains how my f150 works (vacuum modulator on front diff) but it's not setup that way on exp!!

 

[toomanytoys]

Yes it is. It uses a push/pull vac operated solenoid to engage/disengage the front drive. Unless of course yours is awd. Then the front drive would be always engaged

 

[5starChad]

Yes it is. It uses a push/pull vac operated solenoid to engage/disengage the front drive. Unless of course yours is awd. Then the front drive would be always engaged

This is correct. The solenoids are on the passenger side firewall above the ECU.

 

[ddgts68]

I do not have the solenoids or any sort of vacuum operated push/ pull device. I do on my 97 f150. That's my question I don't have any of that. The switch in truck says A4wd/4hi/4lo. does that mean there is some sort of limited slip in the front diff?

 

[ogre20012001]

Your frond diff is always engaged.
It doesn’t have the disconnect like your f-150 has.


Sent from my iPhone using Tapatalk

 

[ddgts68]

Wouldn't there have to be some sort of slip or brake in the diff to be able to turn with out binding and such/

 

[and0r]

i seriously doubt the front diff would always be engaged, that doesn't sound right

 

[toomanytoys]

In a awd system the drive is split around 35/65 front rear. More drive is applied to the front wheels through the transfer case when rear wheel slip occurs. The front diff is always active hence no vacuum solenoid to engage or disengage

 

[5starChad]

Yea if you don't have the 2wd option on your switch it's always engaged. I didn't notice you had a 99. I believe only 97-98 had that.

 

[ddgts68]

Thanks, I was going to change fluid and don't know if I will need to add a modifier also.