Beware with modifing any transmission. I found out the hard way a couple of months ago. My 02 Excursion ran fine other than it needed a fluid change. I thought I would up grade my valve body since I had in older muscle cars. How hard could it be. So I thought. After the upgrade it was much firmer, that was until I was towing a 25' travel trailer. To make a long story short I lost 2nd gear. After losing 2nd gear I called A machnic friend of my he told me that there has been a number of service bultins written, so be sure to upgrade everthing or best yet is to upgrade when rebuilding. beware of upgrading any tranny with miles on it.