[SainT]

Remove stuck plug the best option but I don't think U can apply big force by flat skrewdriver . Better weld a bolt into plug -U will have strong hex head to rotate and U will heat plug area (and this is very helpfull cause alu case enlarges more than steel by heat)
But if U in a hurry and just wanna make it quick - pull off the tube from white plastic part(seen onto Ur photo) and use it to fill the transfer by injecting oil (transfer hasn't another holes to release air so better not to try inject all oil into 1 attempt)

 

[SainT]

One thing I forgot to say - after I read a lot about transfers and oils I changed oil from dex3 to axle oil 75w90-GL5
The reason is the chain -its so expensive and hard to get that I decided use thicker oil with more drag (and fuel consumption of course) to protect it from wear as much as I could

 

[SainT]

. Seen it many times

Will see - I read that old transfer use same oil that used in manual gearboxes. Don't know reasons to use AT oil that actually designed not for transfer cases

The heavier oil will wear the chain faster

How ?

 

[SainT]

with clutches

That is the reason - friction clutch pack that require special oil for proper work
bw4472 doesn't have clutch -viscous coupler sealed and not contacted to any oil into transfer

It can also hurt other parts inside, especially needle bearings..

Transfer cases with 75-90 have them too
Manual tranny have them too
Front axles have them too
Special types of needle bearing ? But they can run even on grease lubricants with no issue if read manufacturers specs
Inside 4472 no parts that can hurt -no oil pump, no brass synchronous

people think

That can spent some fuel onto thicker oil that engineers cant cause of they need to reduce drag for better mileage

, BW4472(all AWD astros, 90-98), and a NV136, 99-05 astros,AWD.

They work different and 136 has clutch that require autotruck2 special oil (and lately GM replace it by dex6 if I remember correct)
Most of ur examples have clutches and its not correct to comparison with current 4472
Morse chain works different than conventional chain such as bicycle chains with rollers
Its not roll but slides onto gears and in such conditions better oil film -less wear

 

[SainT]

without "knowing" why they call for ATF.

Less drag = less fuel consumption
The only reason I see -and its happen not only with transfers -every new engine has 0-20 or less , new tranny 8+ speeds require oil thinner than water to save fuel
And nobody cares longevity if its enough to warranty period
I worked for GM dealer and saw engines and trannys that broke off under 10k and nobody cares
Timing chains that wear off less than 50k at every 3.6 motor and a lot of another common problems
And after I ask GM warranty chief engineer(who controls all dealerships in my country) why it so - He sad me - its cheaper for company to repair than upgrade
In conclusion - I work with cars more than 20 years and have my point of view

. then go for it.

Have done it already actually long time ago

You decided??

Yes why not ?

Could there be reasons you don't know?

Nobody knows everything
Even engineers -they still human

More drag = better protection?

More additives supposed to protect metal from wearing -drag is unpleasant bonus to that oil

What wasn't known is that increasing pressure also increases heat and wear

Its no doubt should be so , more load -more heat. Plain and simple
OEM oil "cooler" for PS not enough for stock pressure -its barely can hold PS system from overheat
And I personally dont see benefits from rising pressure -my steering wheel light enough in comparison to non american cars and it not helps at icy roads

 

[SainT]

u won't make it 10k miles before catastrophic failure.

Man I drove more than 80k on oem worn chain after I changed oil to extend time because I cant buy another
Now my chain from another non american car and its not fit well - because I cant buy even HV-015 -so I make experiment with what I have
I would be very happy if I changed oil to 75-90 right after I bought astro and not have any problems with chain

 

[SainT]

Try not being disingenuous when you quote

And u don't mix classic tcases and ondemand units okay ?
I wrote about 4472 only (and lets add to this similar 4473)
U tried to convince me that ondemand tcases need only atf oil (and I know it clearly and not say anything about change oil in that type tcases)
What is ur point ? They are not the same at all
There is no parts in 4472 that so sensitive to different oil such as clutch driven transfers

My Factory Service Manual says Dexron II.

I work with online manual from GM and it says dex3 because dex3 successor of 2
And after 2006 (correct me if Im wrong) manual says that all warranty repairs should use dex6 instead of 3 or it will be not covered by GM
My point is to think what will be better for me by analyzing all the info that I know and not to follow mindlessly to all modern only because its newest

 

[SainT]

LOL )