Rear Diff Plug HELP

[Diastole]

To All,
Welding square bar was quite easy and uneventful. The plug backed out with little force. The penetrating oil and heat combined with blasting air on the plug to "contract" it all contributed.

See Photos

The inspection hole appears non-tapered. The replacement plug (ordered from supplier) threads in but after about 3/16" to 1/4" I meet significant resistance.
When I compared it to the drain plug a noticed a stark difference.

The drain plug is tapered!


The old inspection plug does not appear tapered, but it is very short.

Please help?

Does anyone know if the housing is tapered for the drain or inspection plugs?
Could one be tapered and one be non-tapered?

I did not chase the threads. If they are tapered I can ruin the threads in the housing. None of the suppliers have tapered plugs. The are all non-tapered or cylindrical.

Should I just install teflon tape or orange Loctite and reinsert?

All the threads look good, both on the plugs and and housing.

A couple of posts said to wash the housing out with kerosene and refill. Is that necessary? The fluid was dirty but not congealed.

Please advise.

Diastole