Ugh, I wish I could help but I'm a bit far... Long Island, NY.
We've been doing Revolution gears & rebuild kits with labor for $2,300. (NY labor is more than other states...cost of running a business here is just ridiculous)
Diesels have more torque so if the 4.88s work well which they do on my 3.6L JT than I wouldn’t think you need anything different. And like Flu said, that pinion gear starts getting pretty Small after 4.88s
I have a shop and we've done 4.88s, 5.13s & 5.38s on new JLs & JTs with 37s. They 4.88s have the most "stock" feel like this is the way it should feel from the factory. Gives it more punch off the line and holds 8th gear at highway speeds without dropping in and out of 7th.
I personally went...