I just put up graded gears in my 231 t-case, and I know your supposed to put dextran III in it if I'm not mistaking but I've also been hearing about putting regular 30 weight oil in it saying it runs cooler. Has anyone heard about this or had any exsperence with it? Thanks

 

Whoa... In an NP231, you can run 90 weight... Thats what we always ran. I don't know bout 30 weight, wouldn't that be like water? IDK, but 90 weight is about equivelant to what goes in there... at least in 2000 era vehicles...