AUTO or Lock when in 4x4
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Senior User
Joined: Aug 2006
Posts: 387
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From: Ballston Spa, NY
AUTO or Lock when in 4x4
just went out hunting today which involved some wheeling and i was wondering what you need your hubs in when you turn to 4x4 high. in cab i just turn the switch but what does the lock do that auto doesnt? can some one help
Posting Guru
Joined: Dec 2005
Posts: 1,334
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From: Parker, CO
Auto with lock and unlock the hubs when you switch to 4X4 in the cab. I have found with mine that they don't hold that well because I have a intermittent vacuum leak. The hubs use a vacuum to lock in, and if that vacuum is weak, they wont hold. I now lock them in if I want to use 4X4 for peace of mind knowing my 4X4 is really working.
New User
Joined: Nov 2009
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I have an 06' F-350 FX4 Power stroke, my 4x4 high and low wont engage from the switch in the cab. truck only has 30k on it, It does work however when i flip the hubs to lock. Also when I ran into this problem I noticed on the muddy grass hill I was stuck on, that I was only spinning one wheel in the rear when in 4x2? so this means i don't have a locker or limited slip in the rear on an FX4, is that possible?
Sorry not trying to hi-jack the thread.
thanks
Sorry not trying to hi-jack the thread.
thanks
Super Moderator
Joined: Aug 2008
Posts: 37,384
Likes: 1,868
From: Frederick, MD
I have an 06' F-350 FX4 Power stroke, my 4x4 high and low wont engage from the switch in the cab. truck only has 30k on it, It does work however when i flip the hubs to lock. Also when I ran into this problem I noticed on the muddy grass hill I was stuck on, that I was only spinning one wheel in the rear when in 4x2? so this means i don't have a locker or limited slip in the rear on an FX4, is that possible?
Sorry not trying to hi-jack the thread.
thanks
Sorry not trying to hi-jack the thread.
thanks
Tell us what that is and we can tell you the type of axle.
I am gona guess since you say you have a FX4 that is gonna be at least 3.73 gears with an axle code of 3L.
Senior User
Joined: Aug 2003
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From: SW ND
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New User
Joined: Nov 2009
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I appreciate the help, my rear axle # 3L-B-CCCC-DO5? does this make sense?
the 4wd problem is a bit frustrating the truck went off warranty about 4 months ago and I had the truck looked over by the dealer to the tune of 100 plus $, and they gave it a clean bill of health. Do you know what it costs to have the leek repaired assuming that is the issue?
Thanks
the 4wd problem is a bit frustrating the truck went off warranty about 4 months ago and I had the truck looked over by the dealer to the tune of 100 plus $, and they gave it a clean bill of health. Do you know what it costs to have the leek repaired assuming that is the issue?
Thanks
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Logistics Pro
Joined: Mar 2002
Posts: 3,881
Likes: 84
From: Wake Forest, NC
Keep in mind it is the vacuum signal that switches the locked state of the hub. The vacuum doesn't hold it locked. IIRC, a high vacuum signal will lock it, low will unlock it. So a weak signal won't cause it to lock.
The lock position overrides the auto setting in the event of an auto lock signal or electric failure. If the hub itself fails, the lock setting prob won't override it.
For the axle tag, you probably didn't see all of the 3L73, mistaking the last 3 for a B, which means you should have limited slip. But the factory ones are pretty weak and what you describe may be "normal" if it was really slippery. It can only transfer so much torque.
The lock position overrides the auto setting in the event of an auto lock signal or electric failure. If the hub itself fails, the lock setting prob won't override it.
For the axle tag, you probably didn't see all of the 3L73, mistaking the last 3 for a B, which means you should have limited slip. But the factory ones are pretty weak and what you describe may be "normal" if it was really slippery. It can only transfer so much torque.
New User
Joined: Nov 2009
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Okay, so I looked up the axle codes and it showed a 3L and Ford shows that as a 3.73 locker, so your assumptions were correct. the thing that gets me is isnt there usually a clunk in the rear when it engages? i was on the gas easy and hard I dont think that it ever locked up, is this an issue I can take to the dealer? or am I better of going and getting a better locker. the truck pulls a horse trailer now 12,500lbs and will soon pull my Sleds, which is where I see this being a bigger issue.
Thanks
Thanks
Laughing Gas
Joined: May 2006
Posts: 1,192
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From: Oakville, Ontario
The way I use mine is when I know I will need the 4X4, I lock it, for easy and quiet engagement. If I don't think I will need it I unlock/manual, if I do end up needed it I could still use it but you will hear the gears mesh.
Logistics Pro
Joined: Mar 2002
Posts: 3,881
Likes: 84
From: Wake Forest, NC
No, because you don't have a locker. You have a limited slip (LS) which is an entirely different type of traction differential. The stock Ford ones don't work that well, honestly any clutch type LS doesn't work so well on a truck. There is lots of information in the forums about ways to improve them, mainly by varying the amount of limited slip additive. Lots of other opinions on this topic as well.
Posting Guru
Joined: Jan 2003
Posts: 2,181
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From: Eastern CT.
Thinking,,,Headviking has the right idea,,,if you may need 4x4,,,lock your hubs,,,,plus it will help keep your hubs freed up!,,,trucks that never get there ESOF hubs turned,,seem to have more of a froze Hub problem!
Course my truck has the Manual Hubs and transfere case,,,,Just the Way I like it!!!!!
Course my truck has the Manual Hubs and transfere case,,,,Just the Way I like it!!!!!
