Hello, i'm interested in upgrading the gears in my current tow rig, so I can tow more without spending a fortune on a whole new truck. My current set-up is limiting my ability to upgrade to a bigger 5ver. Therefore, I want to switch from 3:73 to 4:10 rear. The supply plant is the Vortec 6000/6.0 V-8 gas with 4-speed auto-trans and has a complete heavy duty trailering, suspension and handling package. I have several questions I'd like to have answered. First, since the truck is 4WD, do both axles need to be switched to the same gearing? Second, if I were to make the swap to the 4:10, do I have to make any modifications or changes to the Driveshafts, Torque Convertor or Trans? Third, how will the gear change affect my fuel efficiency(better, worse or the same)and should I replace the gear fluid w/Synthetic gear oil? Fourth, would I see a noticable enough differance in pulling power or would this just be a waste of time and money? Afterall, I'd rather only spend $500-$1000 for parts, then by a new rig, which is completely out of the equation at this time. I'm also thinking about beefing up suspension w/a set of Air-Bags(any good suggestions)? Finally, an upgrade to the exhaust as well should also give me an added boost in Horsepower, Torque and Fuel Efficiency would you agree? Added note: This is not a 2500HD, just a 2500 3/4ton shortbed. With that said, the 2001 Tow Rating Guide states that my truck is rated to tow a GVW of 8600 lbs. Using the same info already given, for the same year stated, the truck has a GVW increase when using the 4:10 rear to a whopping 10,300lbs. This is what started spinning the gears in my head .....

Thanks in advance for any help, Shane Huff - Williamstown, NJ