Sounds a lot like the splines on the front drive shaft (opposite end to the guibo). If the driveshaft was replaced because the splines let go to sell it quickly, they may not have replaced the female spline section in the transfer case, which probably damaged the new driveshaft.

Mine was at the "clink" stage when changing direction when I replaced it. One option is an extended spline length front driveshaft. Have someone watch under the car (from a safe place) and see if you can notice the splines slipping on the front driveshaft. The transfer case chain also can stretch and get noisy. There are some posts explaining how to inspect it through the fluid fill plug.

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David.X5
2001 X5 4.4i Sport
SOLD! at 160k miles