In Marlin's original instructions he wrote in April of 1994, you are told to add gear oil from the transfer case fill hole until full, insert fill plug finger tight, and wait 3 to 5 minutes. Then remove fill plug to find the oil level has dropped (as oil has made it's way into the Crawl Box), and then fill until full a second time and then insert fill plug and torque to spec.
What I like to do is the following, and this is easier with two people:
1. Remove fill plug.
2. Remove Crawl Box shift handle.
3. Add gear oil from the comfort of your driver's seat through the top of the Crawl Box shifter base.
4. Have a friend under your rig at the fill hole with plug in hand and ready -- or continuously duck your head out your cab to see if oil is running out the fill plug hole (and have an oil tray ready).
5. The moment oil begins running out the fill hole, insert fill plug, torque, done.
I prefer this alternate method because any error results in being slightly overfilled rather than slightly underfilled.
Regards,
BigMike
