anyone know about 87 broncos?

As for the Bronco, what comes to mind is rust. Like previously mentioned. I would look at cab/body mounts, leaf springs shackles/ perches, rad support where the body mounts are. You usually can tell a rad support issue because the bumper to body gap is uneven from left to right. Auto trans issues, it probably has 1 rebuild on it. transfer case and rear issues, usually bearings going bad, output shaft and pinion bearings, stuff like that. With a vehicle that old, unless its a low mileage vehicle, expect to rebuild or replace components. I think the rust is the biggest issue, component replacement is straightforward, bodywork is an art.