THe type with the fan on it is what you want, so you can mount it out of the flow of your radiator, otherwise it is adding waste heat to your radiator for it to deal with

not something you need when climbing a real long grade which is when you need the tranny cooler.
Get the larger version that has the plate and fin cooler under the fan though.
THis bad boy will take care of ANY cooling problems
If that doesn't fall in your budget range, there's a little trick that has been used for years that is very effective. Scrounge an AC condenser at a upullit and flush the living daylights out of it ( preferably take it to a radiator shop and have it professionally cleaned out , a day or two of soaking in their soup can get stuff out that nothing else can) As mentioned, mounting that out front will add waste heat to your radiator, but they are so bit that there aren't too many other places to fit one ( unless you have a headache rack and want to string line back there and run remote fans to it )