4 Wheel Drive Engaging - Ford 7.3

[rgood]

Guys, I recently bought a 2000 Ford F250 - 7.3

It has the In-Dash SWITCH to engage the 4 WD.

It also had the lock in - lock out hubs.

My question is - Does the Dash switch control the lock-in/lock out hubs too?

Or is it only engaging the 4WD?

I ask this question as when I'm driving up and down the highway, I want the fuel economy of the Hubs being locked out. So, if my hubs are manually locked out, and I engage the indash switch, is it in 4WD? The dash light says it's in 4WD.

Or to ask the question another way - What do I have to do to use the 4 WD -You would think the operation manual would clearly explain this, but it's about worthless. Thanks!

 

[Reg]

Guys, I recently bought a 2000 Ford F250 - 7.3

It has the In-Dash SWITCH to engage the 4 WD.

It also had the lock in - lock out hubs.

My question is - Does the Dash switch control the lock-in/lock out hubs too?

Or is it only engaging the 4WD?

I ask this question as when I'm driving up and down the highway, I want the fuel economy of the Hubs being locked out. So, if my hubs are manually locked out, and I engage the indash switch, is it in 4WD? The dash light says it's in 4WD.

Or to ask the question another way - What do I have to do to use the 4 WD -You would think the operation manual would clearly explain this, but it's about worthless. Thanks!

I think you need to lock the hubs FIRST.
Then you can use the dash switch.
I think the rumor about economy when running with hubs unlocked is bogus.
It supposes that the drag in the axle and bearings represents a significant work load - - in the scale of moving probably ~7,500 lbs of truck around it is negligible.
You could save more fuel by turning your engine off at stop lights.

 

[cp1969]

If it takes 5 ft-lb to turn the driveline (I have no idea what it actually takes, but 5 ft-lb doesn't seem like much)

And the driveline spins at 2000 rpm going down the road

Then it takes about 1/10th of a gallon per hour (about 30 cents per hour today) to spin that driveline.

 

[Diamondpilot]

I had a 2004 and a 2006 f-350's with diesels and I was told that the hub was simply a backup to the dash switch. As I remember it there was a AUTO selection on my hubs but these trucks were later models than yours.

Chris

 

[ScottAR]

The manual hubs are a backup in case the button doesn't kick the hubs in.
Really nice feature if you ask me. Takes away most of my objections to electronic 4wd besides the "more complex than needed" angle.

 

[Dmace]

The hubs allow you to drive around in "unlocked" or "automatic" position. The "automatic" position keeps the front-end disengaged until the driver engages 4-wheel drive from inside the cab.

It's not a backup, you still need the switch to activate the hubs.

 

[RayH]

The button on the dash engages/disengages the transfer case. The manual hubs engage/disengage the axleshafts at the hubs. The manual habs are not a "backup" for the dash switch, they are for two seperate things. If you engage the transfercase without engaging the hubs, you wont have 4X4. The front driveshaft and front axle will receive power from the transfercase but it wont get to the road because the hubs are not engaged.
If you engage your hubs but not the transfercase, the front wheels will turn your axle and driveshaft when you drive. Its perfectly exceptable to leave your hubs engaged in the winter or any time you may suddenly find yourself in need of 4WD, that way you dont need to climb out in the weather or the mud to engage them.

 

[skipmarcy]

No one has quite gotten it right yet, almost but no cigar. The dash switch must be used to engage the transfer case, no if ands or buts. It shifts it from 2wd to 4wd high or 4wd low all in the transfer case itself, just like the old manual shifters did.

When the hubs are in the manual free position and you turn the switch on, the transfer case turns the axles and an automatic clutch in the hub engages the hub to give you drive. These clutch assemblies in the hubs can give trouble and not engage for various reasons - too cold temperature making the grease real stiff is one cause, worn parts, wheel in a bind, etc. Even when they do work, it usually takes a revolution or two of the wheel to engage the hub. If you are stuck solid or the hub fails to engage automatically, you can get out and manually turn the hubs to overcome the automatic portion not engaging. You must return the manual hubs back to free once you're out of your jam. The automatic hubs will disengage automatically when you turn the switch off (back to 2wd) after a few feet of movement(as long as the hubs are back in the free position manually). In my Nissan, you have to move in reverse a few feet, then go forward a few feet for them to disengage. The Nissan doesn't have the manual overide hubs, totally automatic. In my F250, they disengage without reversing any, just drive a few feet in either direction knocks them out.

Do not run the front hubs engaged either manually or automatically at highway speeds or on hard, dry surfaces. These 4wd systems are not the same as an all-wheel drive system !!! They are not designed to be operated at speed !!

 

[RayH]

Wow, auto/man hubs, thats a nice arrangement. I must be behind the times, my old 97 7.3 had run of the mill manual hubs. when did Ford add the auto option?

I disagree with you about running on dry roads with the hubs manually engaged. If the transfercase is in 2WD, the front and rear drivelines are not connected together, aside from a little more noise and a different feel, there shouldnt be any bad results from leaving the hubs engaged, unless theres something Im missing about the bearings or lubrication of the front axle, in which case, you shouldnt drive it for extended periods in 4WD either.

 

[firemanpat2910]

Buying a used truck means there is no answer without more questions. do your hubs say "Auto" and "lock" or "Free" and "Lock" ? One of the first things alot of owners upgrade is the Auto Shift On the Fly hubs. They routinely replace with 'Warn' brand hubs. On my 07 and my buddies 01 F250s when you turn the little knob on the dash it uses vacuum to activate the "Auto" hubs. If we are going some where that I Know we will have to lock in I will stop some where that I can get out on "Clean dry ground" and pre "Lock" my hubs so that if a vac hose is bad I dont have to get wet feet to "Lock" the hubs. If I just bought a used truck I would test the auto locks. simply chain hitch to Solid tree. put hubs in Auto put dash switch in 4hi SLOWLY drive forward to take slack out of chain. when chain is taught give it enough gas to spin the wheels. stop put in park get out and see if front wheels tore up any grass then repete with hubs in "Locked" position.