Whinning/Grinding sound from under my Jeep...

[GreenReaper93]

Hey everyone! Here's my scare for the week....

Since wonderful Mother Nature has blessed my little corner of the world with about two feet of snow I've been using my four wheel drive as a daily driver to and from work. When I shift it into 4hi it will grind very slightly, then as the RPM's build I can hear this whin/grind sound. I'm guessing it's the steel chain belt in the Trans. Case. I already know there's an issue with the vaccume lines (sometimes the front axle won't engage fully), but do you think that may also be the culpret? Lend me you knowledge! Thanks!

 

[Snitty]

make sure your axles are at the same speed when shifting into 4hi... whether stopped, 2 mph, 10 mph or 50 mph.... as long as the axles are spinning at the same speed.. it should engage safely... but.. if your rear is spinning, and you try to engage... it will try to engage the stationary front to the same speed as your rear.. not good.... a whirring noise is common and somewhat normal

 

[Bounty__Hunter]

Some transfer case whine is normal. Make sure the transfer case fluid is topped off.

 

[GreenReaper93]

Yeah, I usually shift when I'm not flayling aroudn the road like a chicken with it's head cut off :shock: I had the fluid changed and topped off about three months ago. How hard would it be to change the seals (gaskets) on my trans. case? Thanks guys!

 

[Bounty__Hunter]

Is it leaking? Where?

 

[GreenReaper93]

I just looked under it after posting. It's hard to really tell what's water and what's fluid. It was more of a "Worst-Case Senario" type of question.

 

[GreenReaper93]

OK, now I think I'm getting worried... We're having a pretty nasty Lake Effect snow storm here so I have to use my 4x4 to get around town. As I shifted into 4hi I heard a short grinding sound followed abruptly by a BANG! I can only assume the BANG portion was a bad U-joint (my guess is that it's loose/old and in need of replacement). Any clue guys and gals? Thanks in advance!

GR93

 

[Snitty]

a grind, bang, and a jerk is often associated with your rear wheels spinning, and your front tires stationary whild you are pulling it into 4... your rear wheels will cause the rest of the drivetrain to spin, and if the front wheels are stationary, a spinning drivetrain is trying to mate up with a sationary axleshaft... the shift collar tries to spline up with the shaft (grind), the collar and shaft finally engage (bang), and you then move forward (jerk)

 

[TwistedCU]

If it's shifting rough maybe it would be best to put it in 4WD when you're sitting still and see if it still makes noise when you take off.