has any heard of anybody doing this? I think that since it was a factory option on the zjs it shouldnt be to difficult. Will the 4.0 tranny hold up or should I swap it too? Thanks for any info

I don't know if it would bolt up or not. I would say to replace it. Because the tranny is probably tired and probably wouldn't hold the torque of the 5.9. In 98 they built the 5.9 limited, I would see if you couldn't round up engine tranny combo out of one totaled. If you already have the engine I beleive that dodge trucks had the same tranny. I would rebuild whatever tranny you get, they were notorious for going out around 80-100k. If you have more questions contact me I worked in a Dodge Jeep dealership for 10 years and know the techs.