Does an Oil Pump fail often?

[djshimon]

Does the mechanical oil pump ever fail? I have a 1987 4wd van with 232,xxx miles and the oil filter is dry after driving it around for a couple months... i replaced the filter a few months ago when i bought the van and the old oil filter was very clean, almost too clean. I was suspicious of the old filter being so clean(barely oily and the oil was super dark almost grey). So my friends(past mechanic and new mechanic) suggested engine sludge preventing oil from getting to the pump or oil pump-which is practically the same procedure for removal.

Is a non-OEM ok to use? I found one on ebay for around 90$ that's made by Melling. One problem is Tonkin Toyota says the pump has been discontinued(for the 1987)-I haven't checked 1stToyota yet or the other OEM dealers yet. I'll reuse mine if they don't go bad ever. I'd like to not have to do this job twice though due to the time involved to remove the pump and many other parts in the way.

Ok so this may not be entirely 4wd specific because as far as i know the 2wd and 4wd use the same oil pump but on a 4wd it is much harder to remove. This is due to 2 cross braces being in the way-unless there is an easier way to remove the pan than i can figure out?

Ok well thanks for any help folks, aaron