M1083 Transfer Case Fluid Refill Question

[joelnelson1207]

Dear SteelSoldiers community,

I am brand new to this forum and grateful to be here. I just bought a '98 M1083.
I have a question I am 99% sure I know the answer to, BUT want to be extra safe. Also, I have downloaded the TM and reviewed the diagram of the Allison + Transfer Case combination, BUT I just want to be extra sure I am seeing things correctly.

Ok, here's the question:

- I see a drain plug on the Allison Transmission
- I see drain plug on the Transfer Case

Question:

Does the Allison AND Transfer Case share the same fluid supply?

Or put another way, when you refill the Allison with fluid - using the fluid add tube located on the driver side behind the cab - does this ALSO FILL the Transfer Case? Or, is there a SEPARATE Transfer Case fill plug that I am just not seeing with my eyes or in the Technical Manual.

Thank you for answering what is surely a silly question.

Sincerely,
Joel

 

[coachgeo]

,,,,

Does the Allison AND Transfer Case share the same fluid supply?
,,,,,

Yes they share.. yes they fill at same time. My guess is

1. Maybe the Tcase end has a pocket oil can sit in that is lower than the drain plug of tranny so you need that drain to get the last bit out from the pocket after you drain from tranny?
2. drain a little from either end lets you check for metal flakes that can id potential issues. Magnetic drain plugs at each end catch flakes too (if they are magnetic)
3. The main tranny is existing parts of an allison 3000 trans. used in other trucks, buses, motor-homes etc. w/out the tcase. The Tcase is an add on and guess they designed a drain into it for reasons above?

 

[joelnelson1207]

Yes they share.. yes they fill at same time. My guess is

1. Maybe the Tcase end has a pocket oil can sit in that is lower than the drain plug of tranny so you need that drain to get the last bit out from the pocket after you drain from tranny?
2. drain a little from either end lets you check for metal flakes that can id potential issues. Magnetic drain plugs at each end catch flakes too (if they are magnetic)
3. The main tranny is existing parts of an allison 3000 trans. used in other trucks, buses, motor-homes etc. w/out the tcase. The Tcase is an add on and guess they designed a drain into it for reasons above?

Dear CoachGeo,

Thank you for taking the time to reply.

As I said, I was 99% sure this was the case, but now thanks to you I am 100% sure. Thank you again.

I wish you and your family a healthy safe holiday.

God bless you,
Joel