Jim Grant's Tech Tips
'96 Ford F250 4x4, Dysfunctional Auto Hubs
Q:
I have a '96 Ford F250 Power Stroke 4x4 with auto locking hubs. When I
shift the floor lever into 4 wheel drive the front wheels will not engage.
I have tried it on the fly, stopped, in drive and reverse. Any ideas?
-
Tom W.
A:
It
sounds as if one of your automatic locking hubs are not a team player.
All it takes is one disfunctioning auto-locking hub to make your 4 wheel
drive as completely dysfunctional as a 2 wheel drive in slippery going.
The question now is how do you determine just what part of your Ford 4
wheel drive is dysfunctional? A quick test is to set the parking brake
and the transmission in park. Jack-up one of the front wheels and put
a screw driver or small bar through the axle joint to prevent axle rotation.
Then rotate the wheel. As the wheel is rotated the automatic hub will
start to torque-up/engage the axle. When automatic hubs are working correctly
you can hear and feel the change occurring while the wheel is being turned.
Rotating the wheel in the opposite direction causes the automatic hub
to disengage and then start engaging again. Lower that wheel to the ground
and perform the same procedure on the other side. Don't forget the screw
driver! In the event that both hubs seem to be working there may be a
problem with the transfer case. Most often it is one of the automatic
locking hubs that's the problem. Automatic hubs can be replaced individually.
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