Grinding noise while in 4WD

[PAB]

Hi guys,
I'm creating this post because I have an issue with my 2004 Jeep Liberty 3.7l.
When the car is in 4WD, I can hear a sort of grinding noise but I don't know if it's coming from the transfer case, front axle drive shaft or differential but it’s definitely from the middle/front. I can clearly hear the noise between 15 to 20miles/h and I would characterize it has “cyclic”. It becomes very loud around 40-50miles/h (I’ll make a video and post it later).
I have replaced the transfer case and front differential oil and it didn’t change anything.
I have done some research and I’m wondering if it’s coming from a loose transfer case chain (I hope not) or the font axle drive shaft (seems easy to replace and cost about $200).
Do you know if there is an easy way to diagnose a loose transfer case chain or a deficient driveshaft? Do you have any experience with a similar issue ?
Any feedback will help me!

Thanks

 

[Gyro]

Check the front driveshaft rear cv at transfer case.
If the boot is torn or cracked then it (the cv) needs replacing.
See here for repair - LOST JEEPS • View topic - '06 brake line extension

Gyro

 

[PAB]

Thanks Gyro

I'm gonna take a look at it as soon as I can. The link you gave me is talking about brake line extension. I don't get it.

 

[krisP]

http://www.jeepkj.com/forum/f202/how-change-front-driveshaft-change-driveshaft-head-47161/

here yuh go