[sc_rufctr]

That's the problem...

To add/replace the gasket at the differential end you have to take the mid section off.

To do that you have to undo two large nuts at the end of the input shaft and the pinion shaft.
(Not to meantion removing 5th gear, 5th gear slider, reverse gear...etc)
You can only reuse one of these nuts (input shaft). So you have to buy a new nut for the pinion shaft and then torque both back to spec.
The torqueing of these two nuts should only be done on clean/dry gears and shafts....

To replace the gasket towards the nose you can remove the nose section without disturbing the gears but be careful not to loose the small pin
that operates the reverse light switch.