Are you talking the front or rear axle? You mention Dana 35 which is the front but say rear in your post which would be a 7.5" or 8.8" axle, I know some idiots call both axle a rear...
Anyway, being a '90 it is most likely a Dana 35 in front (count the bolts on the pumpkin, 10 is Dana 35, 12 is Dana 28) and if you grab the whole front axle you can get it from a '91-94 Explorer or '90-97 Ranger, '95-97 axles are a bit better in they have dual piston calipers and adjustable steering stops...
For the rear, any Ranger rear axle will pretty much bolt up, '93 and newer are a little bit wider, anything with a 4.0L will have an 8.8" ring gear but still the same 28 spline shafts as the 7.5", and it's hit and miss whether you end up with 9" or 10" drums... The explorer axles are better as they're all 8.8" with 31 spline shafts, '91-94 will be drum brakes and '95 and newer will be disc brakes.
Luckily for you, 3.73 ratio is one of the most common ratios, if the differential still has a steel tag on it the ratio is the first digits on the second row of text, you're looking for 3 73, if you see one with 3L73 it'll be a limited slip axle. If the vehicles in the yard still have a drivers door there's an axle code on it, go to the tech library and look in the axle section and there should be a table to decipher those codes...