what should i use for T-case Fluid

[NateDawg1775]

I'm going to do a tune up on my truck pretty soon so it will hold up better this winter when im gone but im not really sure what to put in the t-case i keep getting diferent answers everywhere i go but just want to know if i should use transmision fluid, or just oil, or if theres something else
Thanks

 

[Bob H]

The 77 manual says 30w oil
the 78 manual says 10w-30 oil (probably best for the winter)
it should have the NP203 full time t-case in it
do not use gear lube or trans fluid.