Bevel drive Crush washer vs O-Ring

[Shuswaper]

It has occurred to me that something might be ass backwards here. I have taken notice that in all the documents I have read so far, an O-Ring is specified for the drain plug on the Bevel housing while a crush washer is for the fill/level plug.
Shouldn't it be the other way around?
Every drain plug on every vehicle I have ever owned called for a crush washer. Seems to me, the o-ring is more appropriate for the fill/level plug where there is less chance of leakage anyways.

What say you folks ?!

[David.]

An O-Ring is specified for the drain plug on the Bevel housing while a crush washer is for the fill/level plug. Shouldn't it be the other way around?

No, the design of the two plugs if different.

Drain plug.


Fill plug.

[Shuswaper]

Thanks for that David, haven't had to do the oil change yet, so I wasn't aware of the exact design difference in the parts !!

Cheers.