i have a 04 blazer and it will shift into 4 hi and 4 lo with no problem but when i put any power into it i hear this loud ratcheting sound. it sounds like it is coming from the front drivers side. if any one could point me in the right direction it would really help.

 

Sounds like the transfer case isn't fully locking in. Could be a weak vacuum to the actuator. A vacuum leak or a blown out diaphragm in the actuator could cause this. Pull the battery and battery tray, the actuator will be located right below the tray. Have someone engage the 4 wheel drive, and see if the cable has good movement.

 

thank you, i was thinking the same thing. thanks again

 

Check the u-joint and CV joint on the drive shaft. I had a weird loud clanking sound and found out the boot on the driveshaft was torn and the CV joint was toast.