My front differential leaks fluid. I’m sure this would effect my 4wd performance (works only sometimes) but would any of you look at other causes first? Thx

 

Where does the front diff leak? One common place is the 4WD engagement sensor. I've battled with mine for long time. Thread tape, crush washer, etc. and no luck. Turns out the leak was coming internally through the sensor rather than through the threads. Once I replaced the sensor - all clear. Not a drop anywhere.
As far as 4WD working intermittently. Can you elaborate a little? What are the symptoms? Is it not engaging, or does it actually disengage on its own? Engagement issues can be due to a faulty 4WD solenoid, or vacuum leaks in the hoses that drive the front diff engagement. If 4WD was not used for long time, the switching ON process takes longer than computer expects, and that will throw an error code. I've overcame that few times by putting it in 4H (C/D blinking with error), then turning engine OFF / ON (while shifter was left in 4H). On more than one occasion, i was able to engage 4H successfully and to get the things moving properly in front end.