Greetings:
The rear ends do interchange, but be cautious about what you come across. Read the codes and make sure you are getting an appropriate gear ratio. The owner's manual will tell you how to figure out which rear end ratio you have. When the pinion shaft sheared in my '83 4 cylinder Ranger (quite a surprise given that it was hardly a torque monster), the wizards at my garage stuck another rear end in - it was obviously completely wrong for my engine and transmission. I couldn't use fourth gear unless I was going at least 60 mph. My '90 2.9 also easily spins the rear tires and my NEW garage says that there is a kit which will convert what I have to a locking axle. This would cost about $600 CDN. Given that the truck has 315,000 km on it, I have decided to go with an old lateral file cabinet in the back and a little less peddle now that things are getting slippery. Make sure you know what you're buying before you lie in the mud to change the rear end out. The wrong gears really spoiled my '83.