Basicly everything. You're testing things & the weak link is what breaks first. Check your u joints, front shock towers to make sure they aren't rotted out, & how the rubber bushings look in relation with the connections to steel, same with the rear spring shackles, then look at all of your body mounts cuz they rust out & you dont want your body & chasis moving separately. Hubs, shocks, bushings, upper/lwr ball joints, & exhaust hangers, all that stuff loves to break when bounced around off road. Remember it's a 36 year old truck, steel structures & bolts are rusted & rubbed thinner from wear since they were new, so they can break much easier. Make sure your radiator cooling fins are clean and clear of mud/dirt before and after, same for the air cleaner as well.
One thing is for sure, if something is wrong, it will present itself while offroading. A liesure cruise down trails at a leisure pace is one thing, & isn't going to hurt much, but if you go flying down trails, jumping stuff thinking your in a tuff truck competition, good chance you'll break stuff & have a heck of a recovery bill at the end of the trip.
You'll hear creaks and groans you never heard before, so make sure your situational awareness is keeping an ear on those too, so you know what the truck doesn't like.
One thing is for sure, if something is wrong, it will present itself while offroading. A liesure cruise down trails at a leisure pace is one thing, & isn't going to hurt much, but if you go flying down trails, jumping stuff thinking your in a tuff truck competition, good chance you'll break stuff & have a heck of a recovery bill at the end of the trip.
You'll hear creaks and groans you never heard before, so make sure your situational awareness is keeping an ear on those too, so you know what the truck doesn't like.
