Transmission NV3550

[tbs1015]

ok guys I have a few questions. Firstly in your opinion what is the better trans for a 97' jeep wrangler. Currently have the NV3550 in there but I have read that the AX-15 is a better trans. Is it a direct swap or what? Secondly, what is a good decent fluid to run in the trans. I have read anywhere from Redline MT-90 to Valvoline 75w-90 to 10w-30. All this to be said, I recently bough the jeep and the guy before me obviously never changed the trans fluid and I changed it and put 75w-90 it (after about 200,000 miles) and now my trans leaks like no one's business. I'm getting the seals replaced soon and I want to know what fluid to run in the trans .Whats gonna keep down the noise and make the shifting more smooth and easy? Also whats the mileage jeep recommends for changing the trans fluid? Any help would be greatly appreciated