Will the rear end from a 2002 Dodge ram 1500 4x4 fit in a 1998 ram 4x4? Both trucks have 3:55 gear ratios.

You need to Measure them and is if one is wider check yoke and make sure it's the same.

You can change rear ends in old cars never messed with newer stuff, but as long as they are the same width and one isn't more narrower it should be a go

I am curious as to whether or not you have tried it yet.... I have researched the difference between a 99 Ram 1500 Laramie Club Cab 4x2 and a 2003 Ram 1500 Quad Cab 4x4..... The 99, apparently, has an axle width that is .6 inches shorter, (79.3 inches) than the 2003, which has a width of 79.9 inches at the axle. I am attempting to research the electronics thereof as well..... If you have any info, it would be greatly appreciated, and I would be more than happy to swap info also... Thanxx