After changing the spark plugs and wires on my 99 ranger I realized that this truck was really neglected, due to the fact that the plugs where rusted in, and all original, almost impossible to change but I managed. I was thinking of what else could have been neglected. Any suggestions for areas to check that tend to fail or should be checked. It is a 3.0 L Flex fuel 4x4 single cab, with 132k miles.

 

Air filter, fuel filter, plug wires, exhaust leaks, anything can be neglected but those are smaller things that can be done at home.

 

See if you can look into the valve covers through the fill hole to see if oil has been neglected. If so, run some penzoil ultra for a bit since has more detergents than other oils.

 

diff fluids and the transfer case fluid

 

check all your fluids. tans, oil, antifreeze. you might want to run some injector cleaner thru it. and a higher mileage oil.

 

first thing I would do is have the trans flushed, recommended by my mechanic to do every 60k miles, and if your truck's engine has been that neglected, chances are its never been done (meaning your 2 times overdue) if your lucky, it will avoid a possible trans failure down the road.
other than that, check for any leaks from the rear main seal (should see some oil leaking between the trans and block)
everything else posted above is also a good idea

 

Camshaft syncronizer.

 

What kind of fluid should I use for the transfer case? Is it just Automatic transmission fluid?