finally got my 4x4 working its a 3 button and put it in 4hi and works fine but when i select 4lo and drive it makes a loud humming noise while driving. havent had 4x4 working for about 8 months cause couldnt figure out whuy it didnt work. but found out today it was a ATC fuse all along... what is the loud humm good or bad and why is it humming for

 

I think your hearing the shaft spin

Mine hums when the 4wd is engaged

 

but it only does it in 4lo. 4hi doesnt do it and can got up to 45-55 mph and no noise only 4lo. could it be cause 4lo is low torque that maybe my front u joint is bad and causing the hum...

 

mine hums in 4lo my 4hi dosn't work i need a new encoder motor that's sitting next to me right now as we speak waiting for it to be installed

 

yea i replaced mine cause thats what i thought was wrong when my 4x4 wouldnt work. it was easy i think two 10mm bolts and and 8mm to unbolt the wiring from the motor. but could it be a joint going bad though

 

Yea i removed one at a pick and pull its 3 bolts and 1 for the plug

 

It is very possible that you have a problem with the front axle engagement; either a bad vacuum line, sticky cable, or problem with the vacuum switch on the transfer case. It likely isn't engaging the front axle in 4HI either, but is just engaging it more in 4LO for some reason, but it could be the other way around for some reason or another.

 

yea i replaced the vac switch on top of the t case. im going to check the cable and see if its the cable cause i do have 4hi and both the front wheels spin. but when i put it in 4lo it acts like its cuting in and out of 4lo.