I have a 99 7.3 I had a vacuum leak in the hubs so I took them off and replaced all the orings. That solved my vacuum leak but when I switch to 4x4 on the dash it does not lock in. It does work when I get out and lock them in manually. When I do lock them manually it is always in 4x4 even when the switch is on 2x4. If anyone has any idea on what this might be I would really appreciate it.
It could be a leak in the vacuum lines or possible still a problem with the hubs themselves. One thing is for sure, you still have a vacuum leak somewhere.
I have heard that if u turn your ac on when hubs r in automatic and take off hard if there is a leak them ac will start blowing out of defrost ! Mine isnt working in auto either but haven't tested theory out yet
Your hubs need a rebuild, or you have a vacuum leak. You verified that you hold vacuum, so you need to rebuild your gear. I suggest Warn in lieu of a rebuild, but a rebuild is cheaper.
When you lock the hubs manually and flip to 2wd, your not in 4x4 unless you have a transfer case issue too. What you will see is that the front drive shaft turns but it will be in neutral at the transfer case so no power goes to it.
As for the auto hubs, like the other said it's either bad hubs or a leak.
When you have the hubs in auto shift into 4x4 and travel several feet in forward, then reverse several feet and then once more back into forward. Do all of this while the a/c is on max. If your a/c changes for the vents to the defrost... It's definitely a vacuum leak.
When selecting 2wd, 4x4, and 4x4low does the transfer case ESPF motor make any sounds? You would hear it clicking... If its not check to if its getting power, if its not, check the relays. If they are good then its probably the 4x4 module. FYI, the soleniod can be jumped bypassing the 4x4 switch so you can rule out that too.
I bought the truck used and no owners manual came with it :/. Might have to pick one up
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Ford Powerstroke Diesel Forum
5.4M posts
265.8K members
Since 2005
A forum community dedicated to Ford F-series owners and enthusiasts with a Power Stroke diesel engine. Come join the discussion about performance, bulletproofing, modifications, classifieds, troubleshooting, maintenance, and more!