Can driving with the hubs locked on my F350 fry the differential? If so, if I unlock the hubs will the vibration stop and is it okay to drive?

Which 4X4 system does yours have ?
Four-Wheel Drive Systems The mechanical-shift 4-wheel drive system consists of the following components:

• Transfer case (For transfer case repair procedures, refer to Section 308-07B ).
• Transfer case shift lever
• Manual locking hubs
• 4x4 indicators
• Shift linkage (hub locks)

The electronic-shift, 4-wheel drive system consists of the following components:

• Transfer case (For transfer case repair procedures, refer to Section 308-07B ).
• Four-wheel drive (4WD) control module (For 4WD control module installation, refer to 4WD control module in this section.)
• Mode select switch (MSS)
• Gearmotor encoder assembly
• Automatic locking hubs (hub locks)
• Pulse vacuum hub lock (PVH) solenoid and vacuum lines

not unless you have it in 4wd
the locking of the front hubs drives the front difff and drive shaft back to the transfer case but that is as far as it goes
if it was a chain , the vibrations would be felt as well with the front hubs unlocked as the chain drives the transfer case and rear drive line
check for the phasing of the drive shaft because if that was removed and not splined back properly that will cause the problem
also while the "U" joints are firm , they may be in fact failed and seized up causing the vibration

no there is no auto locking hubs. 96 chevys have a ifs (independent front suspension) this give it more ground clearance but does not have lock out hubs, the cv axles go into the front differential an spin freely until you put it in 4wd, how this works is your transfercase spins the drive shaft that goes into the front differential an while you put it in 4wd it sends power to the actuator to lock the front differential. if your front end isnt pulling you either popped your 1 of your cv axles but if you did this you would know because it makes a very loud thunking noise while you're driving, my guess is you have a short thats not sending power to the actuator. check to see if the wiring harnesses are connected and check if the fuse that operates the 4wd in the cab of the truck is not blown. also actuators for these trucks are horrible they go out alot. also you can try reversing a few feet putting your truck in neutral an then try putting it in 4wd

FOUR-WHEEL DRIVE SYSTEM

(a) Four-wheel drive control

Use the four-wheel drive control lever and center

differential lock button to select the following transfer and

center differential modes.

The "H" and "L" position of the four-wheel drive control lever

provides either lock or unlock mode of the center differential

depending on the center differential lock button position.

Use the center differential lock system if your wheels get stuck

in a ditch, or when you are driving on a slippery or bumpy

surface. When the center differential is locked, the vehicle

stability control system is automatically turned off and the

center differential lock and "VSC OFF" indicator lights come on

because the function that controls engine performance

As soon as the center differential lock switch is turned

on, the "VSC OFF" indicator light comes on. After the

wheels are out of the ditch or off the slippery or bumpy

surface, turn the center differential lock switch off.

Make sure the center differential lock indicator light and

vehicle stability control system off indicator light turn

off.

"H" (high speed position, center differential unlocked):

Lever at "H", center differential lock button left out

Use this for normal driving on all types of roads, from dry

hard-surfaced roads to wet, icy or snow-covered roads. This

position gives greater economy, quietest ride, least wear and

better vehicle control.

"H" (high speed position, center differential locked): Lever

at "H", center differential lock button pushed in

Use this for greater traction when you experience a loss of

power, such as wheel slipping, in the center differential unlock

mode.

"N" (neutral position): Lever at "N"

No power is delivered to the wheels. The vehicle must be

stopped.

"L" (low speed position, center differential unlocked):

Lever at "L", center differential lock button left out

Use this for maximum power and traction. Use this for climbing

or descending steep hills, off-road driving, and hard pulling in

sand or mud.

In this mode, the braking feeling that occurs when the wheels

are negotiating a sharp corner is further reduced than in the "L"

(low position, center differential locked) mode.

"L" (low speed position, center differential locked): Lever

at "L", center differential lock button pushed in

Use this for maximum power and traction. Use this for hard

pulling in situations the vehicle cannot negotiate even in the "L"

(low speed position, center differential unlocked) mode. Also,

using this mode when driving down steep off-road inclines will

help contribute to increased vehicle stability.

https://secure.drivers.lexus.com/lexusdrivers/info/my-lexus/resources/submit-owners-manual-search.do

Please copy and paste the link above and it will take you to the lexus site. There you will find the owners manual and you can download whatever sections you need for free.

Hope this helps.

It doesn't take long to learn when and how to use your truck's 4WD system. Follow these steps and you'll feel confident about engaging the system the next time you need to get out of a slippery situation.

For a conventional system, where you can select 2WD or 4WD, the instructions refer to engaging 4WD. For trucks with permanent 4WD, they refer to locking the center differential.

Time Required: varies
Here's How:

1. Refer to your owner's manual to find out how to engage your truck's 4WD mechanism.
2. When driving in snow, mud, or just going off road, shift into 4WD when you get ready to leave solid ground. If you have lockable front hubs, lock them for those operations.
3. For severe conditions, use low range if available. Before shifting into low range you must either stop or slow down to at least 3 mph to prevent grinding gears.
4. When you return to normal conditions, shift out of 4WD or unlock the center differential. If the shifter doesn't want to move from 4WD or the differential lock stays engaged, don't panic, becaue the problem is normal and is caused by pressure on the gears.
   
   • Try backing in a straight line about 10 feet and try to move the shifter again.
     
   • If the shifter still won't move, try backing in an "S" pattern while trying to move the shifter.
5. If you have lockable hubs, don't forget to unlock them when you return to dry pavement.

Tips:

1. Vehicles with permanent 4WD are set up for everyday driving, but not necessarily for maximum traction on slick surfaces. Engaging the differential lock increases the vehicle's traction capabilities.
2. Do not operate a locked 4WD on dry, hard surfaces. Doing that could cause damage to the driveshafts, differentials or transfer case.

What You Need:
Owner's Manual

Good luck and remember to rate this solution.

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i'm assuming you have a 4 wheel drive. If that is the case then yes cause when your in two wheel drive mode the front is in neutral

My 2003 Silverado has done this several times. This happens (at least on my truck) when I switch from any other mode to 2H when the truck is not moving. The front hubs are locked in the engaged position (actually, it locks inside the front differential) when in 4HI, 4LO, or Auto-Trac. When switching to 2HI, the front hubs try to unlock. The mechanism may bind, especially if they haven't been used for months, like during the summer, and don't completely move to the unlocked position. A switch tells the controller when unlocked, but doesn't always get triggered when the hubs don't get completely disengaged. Usually cycling between 2HI and Auto-Trac while driving will free up the hubs and make prevent the problem of all 4 lights coming on at once. Turning the engine off and then restarting it will usually correct the problem with all 4 lights lit at the same time by resetting the transfer case controller. Then, you will be able to switch from 2HI to Auto-Trac and back to 2HI while driving, as described above, to free up the mechanism. If this doesn't fix it, you will likely have to replace the switch in the front differential that tells when the hubs are completely disengaged, or, more likely, the motor that disengages the hubs/drive axles in the front diff.

Could be a few different things. I really doubt the carrier is bad on the truck. I would be looking at the axle half shaft u joints on both sides, and or the cv and u joints on the drive shaft to the front differential. If one of these u joints are bad it can make all kinds of noise and cause vibrations. Especially when under a load. Good luck.

by any chance have you unlocked the rear differential on the hub??

do you have automatic hubs, or do you have to lock them manuelly?