TRANSMISSIONS
When it comes to transmissions, you once again have a handful of choices, depending on what you do and how much you want to spend, first you need to choose automatic or manual. Then it all goes from there! An automatic transmission will generally cost you a few thousand extra, and some added time in the end compared to a manual. The nice thing about a manual is that it will always shift exactly how you want it to, every time, day in and day out. Again, its your choice, just do your research!
Automatic-
If you are absolutely dying to run an automatic in your truck, plan on spending some extra dough to make sure it is done the right way. The best Cummins/auto trans conversion recipe is a 2005ish CR motor, with a Dodge 48RE transmission which is run through the factory computer. There are other options, such as using your Ford 4R100, or 5R110, in conjunction with a standalone controller and adapter plate.
Pros-
-No Billy Big Rigger stereotyping
-No having to shift gears manually
-Easier for stop and go driving styles
-Better suited if you are trying to drag race
-Anyone can drive your truck (If you let other people drive your truck that is!)
Cons-
-More Expensive
-More Time Consuming
-May not always shift the way you want it to
-More possible issues
Manual-
Ah the beauty of a manual! So much simpler, much cheaper, it always shifts just how you want it to, no worrying about wrong shift points, it won't leave you stranded on the side of the road, it will cut out alot of guess work and save you a couple weeks on your total conversion! A manual transmission will just always work. Period.
Pros-
-Much less expensive than an auto
-Always shifts dead on how you want it to
-Nothing to go wrong internally
-Lasts forever, no rebuilds
-Takes abuse or heavy hauling much better
Cons-
-Not always fun to drive in congested stop and go traffic
-Not just anyone can drive it