I hate to burst your bubble, but I think what you are referring to is the GM "corp" 10 bolt. It is not the same as the isuzu Corp 10 bolt. They aren't interchangeable. Also, our 10 bolt is up front, so you'd be trying to hook up 4wd in that case to save gas mileage..... As Triathlete posted, our rear is a 12 bolt isuzu. You really won't save a ton of money(mileage) going to lower gears, unless you have either excess torque or horsepower either. If you could get used to the VX driving like an anemic shadow of itself, I'd say go for it, but you'd be pulling it out of the powerband it was designed for. To get the same speed using higher gearing, you'd be lugging the engine. It was mentioned earlier in this thread that we don't know your specifics, so maybe you've already thought all this out, so if I were you, I'd see what gears were made for ISUZU Corp 10 and 12 bolts and then take a look at both the pros and cons before I went and did it. It was also mentioned that we don't know your degree of mechanical skill, but I'll just throw out there that setting up a ring and pinion isn't done with a set of wrenches and a lazy Sunday afternoon. Shops charge a decent amount of coin to set them up because they require some special equipment. As I said, you may already know all this, but then agian, maybe you don't. Just throwing in my two cents.