I don't know anything about the little Cat, but I really doubt that there are any store-bought adapters to match one up where a 3.0 Vulcan was, so you would have to make a custom adapter.
As far as the trans standing up to the Cat, the Vulcan had 140-150 hp, (maybe more in later years) but torque @ RPM is what will kill a transmission. I would compare the torque curves of the 2 engines, rather than just max horsepower.

 

How would I go about making a custom adapter?

 

Making an adapter will probably require a welding and machine shop plus lots of very accurate measuring. One must make a pair of flanges, one that fits the engine and one that fits the transmission, these must be positioned the correct distance apart so the torque converter can bolt to the engine. (probably will need a custom flex plate to connect the two) All the while remembering that the crankshaft and the transmission input shaft have to be concentric within a few thousandths of an inch. It might be a whole lot easier to find a transmission that fits your engine and adapting the combination into your Ranger.

 

Believe that engine came with an SAE 4 housing and offered 3 possible size flywheels, SAE 7-1/2, SAE 8, and SAE 10. Might talk to the folks at Phoenix Casting and Machining. They have adapter parts for SAE 4, but like Steve stated probably not for your specific transmission. Going to require some custom work.

 

I have a compound turbo vw tdi in my 2000 ford ranger as a daily driver. I don't mean to come off negative, so please don't take any of what I say that way. There's just some hard truths that need recognized when doing a project as large as an engine swap in a somewhat late-ish model vehicle.

#1 - don't run a computerized auto trans unless you're proficient and confident with an aftermarket tcm or tuning software. If you have to ask how to control it, it's not for you.

#2 - you'll want more than 75hp. When my 3.0 lost a cylinder, it was beyond a slug. If you can't tune the Cat up to at least 130-140hp, abandon the ship. My truck currently has about 210whp and it's just right.

#3 - If you have to ask how to build an adapter plate or simple things like engine mounts, it's not a project you should undertake unless you have LOTS of time and a strong desire to learn the hard way. Buy an adapter kit from a company who has stuff on the shelf for a VW TDI, IDI benz, or whatever else. While I have all the tools and know how to build my own plate and crank adapter, I used a TD Conversions kit in my ranger as it saved me 10+ hours and let me put that time towards tube work and wiring instead.


Here's my ranger swap thread if you want to see a vw install https://www.therangerstation.com/forums/index.php?threads/b3000-tdi-swap.171730/