4x4 shiftin issue

[catfisher81]

I own a 1991 4x4 4dr. xlt. It has a 4.0 and a 5 speed manual trans. I went 4 wheelin the other day and got stuck in a mud whole. so i am sittin there at a dead stop with the vehicle running and i reach up and hit the push button 4x4 and the light comes on, however my back tires are the only ones spinning. some one pushed me out. while i was rolling back on dry land again at about 2-3 mph i hit the 4x4 button once again and i heard it engage and the vehicle bogged down like it was in 4wd. so i guess my question is this.
Do you have to be moving at a slow speed to engage your automatic hubs with pushbutton 4x4???:exp:

 

[walterd140]

No, they should engage at a stand still. But if you were at a stand still, engaged, then rocked the truck back & forth you might have knocked them out of 4wd. It's a momentum thing