Bout to cut into trans line. WHY are these different sizes?

 

It's a universal kit, so I think they include those sizes on the chance that one of them will fit your vehicle's factory lines.

Since we cut the 3/8 hose section on the Jeep's lines, none of that screw connector stuff applies. I tossed those and got simple 3/8" barb-to-barb connectors. Several others have posted that they did the same thing. You could use what's provided, but it's a lot of extra bulk with an unnecessary threaded connection.

Here's an example... 3/8" Barbed Brass Hose Coupler

 

Don't use those. Use some with the 3/8 coupling found at ACE hardware or Lowes. Make sure they have deep cut outs like those pictured.

I used some that came from O'Riely auto parts and they were terrible. Leaks came when the hoses got hot and cooled. Avoid the drip drip and get the right ones up front.

 

Finished. Everything looks good. Used what was provided though the hose was about 4" to short. Extra trip to auto parts store. Agree, do not like extra fitting. I will replace those when I get a chance.