In reply to phils question
Auto fluid is fine for the type 9 box, fords originally stated hypoid ep80 when they first introduced the type 9 but to be quite honest the synchromesh on type 9's have always been a bit on the lazy side and auto fluid helps no end, I have been reconditioning gearboxes for 16 years and have always used atf in type 9's and never had a problem.
As for the seal putting thicker oil to stop it leaking wont work if the seal is worn out the only remedy is renewal,
First you do need to remove gearbox(sorry!) then once on floor remove clutch arm and release bearing then you will see a cover which is the guide sleeve for the release bearing this is held on with four 10mm head bolts undo these then gentle tap cover and pull off, then using a blunt screwdriver lever old seal out and tap new one in using a suitable size socket...dead easy takes 2 mins to do the seal but unfortunatley hours to get the gearbox out ;(
hope this helps