I have a 90' 3/4 ton 4x4. The problem is i don't know a lot about it. I've been trying to find some site where i can find specs on it. Things like the rear diff. ( i think its a 4/1/1 ) I also was wondering about the effects of bigger tires and rims. some people have told me that bigger mudders will screw up the 4 wheel drive. Does anybody know what effects putting bigger tires on my kind of truck would trigger? Are there any ways around these if they are bad? i would really appreciate the help.