Super 40's vs 46k

It all depends, if you are purely offroad then you'll want 46. But there are alot of people who use super 40 offroad all the time, for example peterbilt.

I was told with a Pete that both super 40 and 46 are the same, 18" ring gear etc but with 46 it is double framed at the diff. And with the double frame you cannot get low air leaf suspension which is why most guys with Petes have super 40.

But I was also told by the owner of my local heavy truck salvage yard that super 40 are a joke, complete garbage and no stronger than a 40. He said there are some heavier parts in the super 40 that you would find in a 46 but there are also some weaker parts you would find in a 40 and you are only as strong as your weakest link.

I personally tore through muskag everyday fully chained up with mud to the point my fuel tanks were dragging, it was a regular occurance that I would be told to gun it to get to my oil tank to load knowing I would get buried and that a dozer would just come drag me out, and I did all of that with Rockwell 40's and never had a issue, but Rockwell only makes 40 and 46 because their diffs are strong as they come. A Eaton 40 would explode.

Hope this helps.

 

super 40's are a joke, most new trucks come with them, basically replaced the 40's, if your are going to work it hard off road 46's are much better