Mile Marker 501 conversion to NP203

[zac]

I finally got mine done, nobody asked, but here's what I learned. I thought it might be helpful to the average guy as I am not particularly skilled or knowledgable.

It would have been nice to have a brief explanation from the instructions on what is supposed to be accomplished. The first page says "Make you own shaft type conversion," I eventually figured out that you are using the planetary ring, the cross shaft, the output shaft and the wedges from the kit to make a single unit. It might just be me as I am one of those pain in the arse people who always has to know "Why?" instead of just following instructions. When accomplishing this, the instructions just say "Reassemble as in Figure 7 and 8." That's a little sketchy to me because this seems to be the heart of the whole conversion, and the pictures are horrible. One like I'm posting below would have really helped. That unit is now your "shaft." But again, I figured it out and lots of other people have too.

The instructions make a big deal about which way to install the cross shaft, but it never says that you are reversing it from it's original position. Again, I figured it out, it's just the clarity of the instructions I have an issue with.

The speedo gear caused me some trouble. It came off in the housing when I pulled it off, just sitting back there loose. Reinstalling it without taking the rear section of the tail housing off seems to be impossible. The directions direct you to take it off anyway if you have to adjust the endplay of the shaft by adding or removing shims behind the speedo gear. I had to take out 2 of the 3 original shims to get it right. Do yourself a favor and take the back of the housing (6 bolts) off from the get go.

I have no doubt I may have made this harder on myself than I had to, go ahead and tell me what I should have done. I can see where people have some doubts about the torrington bearing/spacer set-up you install. I have no doubt that the warning about making sure to run the case in lock every couple hundred miles for lubrication is very critical. It's too soon to say how my mileage has been affected. But it's very obvious the drivetrain has been massively "unloaded." Noise is reduced, the truck coasts now, and I can turn a corner without hopping. Even if the mileage is the same, so far I would say the conversion was worth it, and it wasn't really that hard in spite of my whining.

[Benelli]

I'm very happy with my conversion. It added about 2mpg (from 7 to 9 is quite noticeable)

I run my hubs locked or throw the t-case in lock at least once a fill up.