engage 4WD and hearing a sound

[My01yuk]

I have an 01 yukon slt 4WD. Yesterday i decided to take the family for a quick off road ride, nothing fancy just a few minutes of off roading. As I approached the turn to go off road i put it in 4WD. I noticed a sound almost like grinding. We were probably off roading for 3 minutes and then i went back to normal road conditions and put it back in 2WD and the noise stopped.
We went to a store and when i got back in, before backing up i put it in 4WD again to see if it made the noise while going in reverse, I heard it again and then it seemed like it didn't want to go so I put it back in 2WD and all was fine. As I put it in drive i again put it in 4WD and heard the noise again. I'm think it's my wheel hubs but can't be sure as I am clueless when it comes to 4WD. What little I have learned I have learned on here. Any ideas?

 

[swtz71]

when it was in 4wd did you actually have 4wd?
was it making the noise at all speeds? I am wondering if it was half engaging causing the 4wd actuator to malfunction.

 

[PUGLIA]

Did you put it in 4low or 4Hi?

 

[My01yuk]

when it was in 4wd did you actually have 4wd?
was it making the noise at all speeds? I am wondering if it was half engaging causing the 4wd actuator to malfunction.

Yes I actually had 4WD, i felt the transfer take place. It may have only been at slow speeds.

Puglia...it was 4HI, I hope to never have to use 4LO as I have been told it is hard to get it out of 4LO.

 

[NY SWAGGER]

Did you put the transmission in neutral before switching the transfer case from 2WD to 4Hi?

 

[My01yuk]

No I didn't think I had too. According to the instructions in the owners manual it says you can put it in 4Hi at any speeds so i interpret that as it does not need to be in nuetral, never have before and it worked just fine. I'll go back and read the owners manual and double check.

 

[redemn93]

trans does not have to be in neutral to go to four high. but i dont recommend doing it at highway speeds. luckily, the computer will block you out if you have 4lo by mistake

gotta be somehting inside the front diff or Tcase no?

 

[MASS-HOE'Z71]

Shouldnt have to be in neutral to go into 4hi but i believe the right way to go into 4hi is by going real real slow and putting it in neutral then 4lo. Only thing i ever hear from my front axle is when im in 4wd and try taking a sharper turn and i hear a little binding but it did that when i was stock suspension/ wheels. If it wasnt a fluid level in the front diff issue, might not hurt to pay the few bucks and have a shop look at it, auto 4x4 transmissions arent the simplest things to play with

 

[Frankhenrylee]

I am interested in this as well. I put mine in 4hi due to some bad road conditions today and it was making some sort of whining grinding sound. If you figure out what it is please let us know. I'm going to change the fluid this weekend and report back. Funny thing about mine is that I had in 4hi a few weeks ago and didn't notice anything. It's been cold here, but not super cold, maybe 30's for highs this past week.

 

[Blkthrn]

Yes I actually had 4WD, i felt the transfer take place. It may have only been at slow speeds.

Puglia...it was 4HI, I hope to never have to use 4LO as I have been told it is hard to get it out of 4LO.

Is it a push button or manual transfer case? If it's a push button, as long as it's in neutral and stationary, switching from 4LO to 2HI or 4HI shouldn't be difficult, the computer wouldn't let you without being in neutral anyway.