Clicking noise while reversing

If there is no driveability issue then I would not worry about it.

The 4X4 on your vehicle is controlled by a electronic control module .
Service 4 wheel come on ? DTC'S - diagnostic trouble code's are stored in the transfercase control module . Your best bet ,take your vehicle to a qualified repair shop

sound like transmission failure.

cv joint i believe the whole axle has to be replace on that model

Sounds like it might be a bad driveshaft universal joint.

how well does reverse work and check color and level of trans fluid with engine running and warm also feel for grittyness of fluid if gritty and browning your trans may be going out

check front and rear u joints in driveshafts

does it click while reversing straight or while turning? Sounds like a stick shift. Lunging probably due to e-brake needing adjustment(if stick shift). If your car only clicks while turning in reverse you need new front axles and can probably drive that way for a while

Check your universal joints on your drive shaft front and rear. Does the truck make a funny niose in reverse? Sure sign of bad universal joins being bad. Does the noise go away when you let off the accelerator? The best way to check them is with the trans in neutral and the parking brake set and wheels chocked. You may see a lot of rust around them and play. Hope this helps!

do you know ware the clicking noise is comming from? maybe relay? maybe bad sellinoid? the sellinoid is my guess.