ESOF question

[fullthrottle99]

Hi, my truck is an early 99 with ESOF. The guy i just bought it from said I gotta physically lock in the hubs to use 4WD. I looked at the hubs and they have an AUTO and LOCK position. Does AUTO mean I don't have to turn the hub and if I shift to 4WD it will work just like it is set to LOCK?

 

[bushpilot]

there are TWO modes on the hubs...AUTO <should> lock when you flip
the ESOF switch on the dash.

in the EVENT that a hub (or both) dont lock w/ the flip of the switch then
you can POSITIVELY lock the hubs by turning each hub dial/switch to the
"lock" position.

when in AUTO mode the hubs are vacuum locked by the flip of the ESOF / dash
switch.

It COULD be that the PO had a problem w/ the Vacuum system and never
bothered to figure out what was wrong or fix it.

 

[95_stroker]

It COULD be that the PO had a problem w/ the Vacuum system and never
bothered to figure out what was wrong or fix it.

I think I concur.....

 

[fullthrottle99]

well, after a vacuum line inspection i've detected that the front left vacuum line to the hub is indeed broken. that must have been why he said to turn the hubs. thanks guys...now i gotta fix a hose.

 

[black_cloud_stroker00]

just yesterday I flipped the 4x4 switch on while the key was on, but truck not running. I was amazed how loud the hubs engaging are. Works great though.

 

[Red Monkey]

Pat,
How did the hubs engage if the truck was not running? I'm not following you here, please explain.
Hal

 

[platinum01]

Yes please explain. Were did the vacum come from? I have never heard my hubs engage but have felt them lock in and pull really hard.

 

[black_cloud_stroker00]

you know, I didn't even think of that. I wanted to test the switch and there was a clear cut vaccuum sound and then a loud click. your guys trucks don't do that?

 

[DaveBen]

There is an electric operated vacuum pump mounted on the passengers fender. You can hear it run if you turn on the key in the morning.

Dave

 

[black_cloud_stroker00]

i knew I wasn't just hearing things