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Anyone know how much ATF is supposed to be put in a NP 203 transfer case

micahsa15

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Hi everyone. im new to these forums. Here's my first post

Anyone know how much ATF is supposed to be put in a NP 203 transfer case
 
As far as I remember the 203's took 30 weight motor oil or gear oil, can't remember for sure, but definately not ATF.

The 208's and the 241's are the only ones that take ATF. If you do infact have a 208, fill out your profile, then it is 4 quarts.
 
203 t-cases take motor oil

208 and 241 t-cases take ATF

205 t-cases take Gear oil OR ATF (later model yeaars used ATF to reduce parasitic losses)

Chris
 
Re: Anyone know how much ATF is supposed to be put in a NP 203 transfer cas

Hmmm ATF is what came out of it. I wonder if the goons that did my NP 203 full-time -> part time conversion put ATF in my NP-203

(stock T-case from 76 Blazer)
 
Re: Anyone know how much ATF is supposed to be put in a NP 203 transfer cas

Definately motor oil, 30wt. Gear oil to heavy, atf not good enough to lubricate the chain well, so I think... /forums/images/graemlins/thinking.gif
 
Re: Anyone know how much ATF is supposed to be put in a NP 203 transfer cas

well then I really have a puzzle on my hands. First: why is there ATF in there now? Second: did the conversion kit that less shwab put in change the lub requirements, third how much do I put in.
 
Re: Anyone know how much ATF is supposed to be put in a NP 203 transfer cas

Definitely 30w motor oil is what goes in them. The guys that did your conversion probably use to working on newer stuff and thought they new everything rather than looking it up. Lube requirements have not changed. As far as how much put it in and keep filling until it runs out. Then its full. /forums/images/graemlins/waytogo.gif
 
Re: Anyone know how much ATF is supposed to be put in a NP 203 transfer cas

[ QUOTE ]
well then I really have a puzzle on my hands. First: why is there ATF in there now? Second: did the conversion kit that less shwab put in change the lub requirements, third how much do I put in.

[/ QUOTE ]

Sounds like a seal problem to me. Check the front input shaft seal. Your tranny is leaking into the t-case.
 
It definetly takes 30wt, and I used to run a little power punch in mine w/ the 30wt. Just fill it till it comes out the fill hole, should take a few quarts.
 
Re: Anyone know how much ATF is supposed to be put in a NP 203 transfer cas

Roger that! Thanks for the help guys. Now last question which one is the fill hole?
 
will it hurt anything to use gear oil, rather than motor oil? I just swapped in a th400/203 in place of my old th350/203, and I was told to use gear oil, so that's what I filled it with. I haven't even used it yet...do I need to drain this out, and fill it with 30wt, or will it be ok? I believe I used gear oil in my last one. it has a part-time kit in it, if that makes any difference.
 
[ QUOTE ]


205 t-cases take Gear oil OR ATF (later model yeaars used ATF to reduce parasitic losses)

Chris

[/ QUOTE ]

How can I tell what mine takes? I don't know what year it is from; it has a slip yoke rear output, mated to a TH350, and has two seals in the adapter. /forums/images/graemlins/dunno.gif
 
ATF won't really hurt it. Actually it will keep it nice and clean but it is specified 30. A lot of folks up north (where -20 happens up north) will run ATF winter and oil for summer. I run 10W30 in mine with no ill effects.

Gear oil in a 203 doesn't move. The 203 has a pump to drive oil up to the top chain gear bearings. The gear oil is too thick when cold to get pushed there and the late 70's 203's had plastic pumps and gear oil could break them.

Do keep an eye on it and make sure that it is not a failed seal between case and tranny. It's doubtfull it is because that part of the tranny has no pressure on it. It drains right into the pan but nose up it might make it into the case. It would be worth paying attention to the levels and making sure your tranny is not looseing the case gaining.
 

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