02 X-Type 3.0
If I run the internal self diognostics test that the car has built into it will that show me if the transfer case oil is low. I've had a small drip after the mechanic filled it up and want to verify if it is coming from the overflow pipe or if I need new seals. The drip is in the middle of the driveway and under the car there is oil everywhere due to this.

 

Unfortunately, the internal self diagnostics are only for the electronics of the Instrument Cluster and some info that passes through it - it's of little practical use (IMHO!). The only safe, certain way to check how much oil is in the transfer box is to drain it via the fitted drain plug, at which point it will have 250 mls left in it. Then add 300 mls and it will have the recommended total. Now clean up the exterior - not easy! - and if oil appears, it will not be from the overflow. Potential leakage points are the drive shaft seals, or from behind the countershaft nut on the righthand side looking forwards, or from behind the nut securing the output flange to the rear wheels. In case you don't know, the design filling point is not realistically accessible and you have to refill through the drain point using one of a number of imaginative methods covered elsewhere on this forum and others!