I want to add a cooler to mine 1997 4x4. It has a steel line cooler in front of the radiator, but I like you want a good finned cooler. I will do as I suggested to you when I do mine.
Also, If you add a bottle of LUBEGARD to your tranny that will help also. It comes for different fluilds. I believe your truck uses Dexron III. That will be the RED BOTTLE of LUBEGARD.
I got my tranny so hot a few months ago it started coming out the vent tube. It was burnt so bad I figured I was in for a NEW TRANNY. Well I had it flushed, a new filter, & pan gasket installed & it is working great. When I talked with the mechanic that did the work he was real surprised it even pulled off the rack. I'm a retired mechanic & had put LUBEGARD in the tranny before we towed a 5000# trailer 700 miles. The only reason I believe that tranny is still working is because of the LUBEGARD. I know a tranny shop that did a few tests with LUBEGARD & found that a tranny will run about 40 degrees cooler with it. I'm not a representative of LUBEGARD just a customer.
PS the mechanic that did the work agreed with me that LUBEGARD may of been the savior of my tranny. He uses it in all trannys he services as do most good tranny shops.