how do I find out what my transmission ID model is? /2005 /3500/ 5.9 cummins /single rear axel

Look in your glovebox for your owner's manual, this would carry more authority than any one of the gurus.

Yeah the manual will tell you. But if its an automatic or manual, and I can tell you

I have a manual 2006 5.9l any clue what tran i have?

6 speed manual is NV 5600. Should be a tag on the back of tranny tail shaft left side. Download the manual from website called just give me the damn manual. It’ll tell you what kind and how much fluid you need for everything

I ran 75 90 synthetic in nv 5600 and front and rear diffs got 1.5 million outa it before I sold it never changed fluid but one time never had a issue at all

98 up to 2005 had nv 5600 cast iron trans with aluminum bell house 2006 and up have the g56 all aluminum another way to tell is reverse is all the way to right and up on nv5600 andthe stick is straight . G56 is other way and the stick is bent funny