Jremmy21

So about 2 months ago i started hearing a slight grinding noise under my jeep. the noise seems to be coming from right under the driver floor panel. about 3 weeks before i heard the grinding i had driven off a highway doin about 70 (long story). i got underneath my jeep and listened while my buddy reved it up to about 40 mph (around 40 is when u start to hear it). it seems like its coming from the transfer case. i went on shop key and they say that if you hear this grinding noise coming from the transfer case just swap the fluid/the fluid may be low. i was just wondering if anyone has had this issue before because around the same time this started happening when ever i make a sharp turn my jeep make a sort of "clunk" noise. it almost seems like its getting caught on something. if anyone has had this problem before i would like to hear your opinion/advice on what it is and what i should do. Thanks