How much chain deflection is allowed on a BW 1356 for the drive chain?

I opened up my transfer case to find it was low on oil, the range fork for the range select was badly worn and nearly on failure, and looks like the oil that was in the case was carmelizing on all the parts. I guess my next step is to fully disassemble and replace the bearings due to the oil carmelizing in the case. Then ordering the replacement shift fork along with the seal and bearing kit. I just want to know how much deflection is allowed on the drive chain. If I got to replace it, I rather do it now when it is apart.