Hello, I'm new here. Mainly here to find out how or what to do after I installed gears in the rear. I have a 2003 silverado. 5.3. Went from 3.42 I guess to 3.73. Speedo is fast and the Trans shifts alittle weird. It has a cat back exhaust. I use the truck for towing my race trailer. Any help as to who to call would be great. Thanks in advance.