I got an issue with humming noise coming from maybe the transfer case of my truck (4wd not engaged) and when i got fast enough i hear a clanking sound when the 4wd is engaged. I can drive my truck with 4wd not engaged but on low speeds I hear a humming.
I cannot tell whether or not the truck needs a new differential or transfer case? I doubt its my front drive shaft.

i got a ford f150 2017 5.0 102,000 miles

 

Have you ever checked/changed fluids? Transfer case uses ATF not gear oil, FYI.

 

i never checked it however the previous owner treated the truck like crap. I bought it at 80k and 4wd would make weird noises every once in a while but ignored it since it was only once in a great while.

When i was driving on the mud a day ago. I switched to 4wd allowed 4 secs to engage while in neutral out of no where when i gave it probably too much gas i hear a loud BANG and heard a grinding sound.

This morning i was trying to confirm whether or not i need a new transfer case i pulled it to the road and had my girlfriend drive while i was trying to listen where the noise was coming from and it made nothing until she drove fast enough and made another banging sound. no rattling

 

i was not able to confirm the fluid levels

 

There have been a few front axle bearing failures. I'd say users here have posted more about front axles failing than transfer cases failing.

What trim is your truck? This determines the type of transfer case.

XLT and below front end is not turning in 2 wheel, so the noise should stop in 4H.
Lariat and above the front also rotates in 4H due to fluid friction in the clutch pack.

 

I have an XLT

 

Most likely not the front differential, if the vacuum IWE hubs are working.

What about a front wheel bearing?

 

There was a post I made however it hasn't come through.



The moment I noticed the issue I was driving on the mud. I switch my truck to 4WD while it was neutral waited 4 seconds to give it time to engaged. After that I switched to drive and gave it a little gas since I wasn't moving since its mud so I gave it even more(Probably too much) and it sounded like it was gears smacking each other and not full engaged. I immediately got out of the mud and switched it to 2wd when the truck was straightened up. My friend who was nearby thinks he heard the noise from the T-case. But that's why I’m here to make sure that's what it is.



This morning, I decided to check again to see what’s going on and had my girlfriend drive

I told her to stay in neutral switch to 4wd (HI) then wait 4 seconds before switching to drive. she drove forward and heard nothing. she was driving 5mph tops.

I got into the truck and I had it go 10+ then I heard a loud SLAM then immediately switched it back to 2wd

 

I had a somewhat similar experience with my 2016, it took a lot of having the front tires off the ground and seeing when stuff would engage and disengage to figure out that solenoid for 4WD was bad. It was in 4WD, I was spinning the tires, and it made a bang that sounded really expensive, and I lost 4WD. The solenoid was not working right causing some vacuum to get by and partially disengage the hubs.

You can test simple enough, undo the vacuum line that goes to the hubs from the solenoid. See if it acts right, easy fix to change that solenoid if that's the issue. I found one of the vacuum lines to the hub had come off and it must have sucked enough dust in to take out the solenoid. Swapped that, plugged vacuum line back in and has been good since.

 

I'm assuming you are referring to this part.

I replaced the vacuum valve next too it however not the actual solenoid