Yes, the existing hoses push on to fittings on the cooler and are held on by typical automotive clamps, they're not exactly the same a hose clamps but do the same thing. You'll need to cut you're 3/8in lines but still use some of the length, install the fitting that goes up to 1/2in then install the 1/2in line on that this then goes to the new cooler, use the new hose clamps that you bought on either end of the new fitting to secure the hose ends to the fitting. I'm probably going to go with the 31 pass cooler just because I might as well get the biggest one in there and be done with it. You can find them on ebay and they usually go for about 250-280 shipped, they used be less but more and more people are doing the mod now so it's more popular. Also check out
Powerstrokeshop.com - PSD and Ford Superduty Parts they offer 3 coolers, two versions of the 26 pass and the 31 pass. The 31 pass is $295 and there is two prices for the two different 26 pass one is $265 and one is $285. I asked them about this and they basically told me the 26 pass coolers are the same but ford used them in different applications so they are priced differently. I've heard the temperature difference is very noticeable going up to the 6.0 cooler and I don't think you can go wrong with either one, but I'm just going to go with the 31, the cooler then better for the trans I guess.