I purchased a 98 mountaineer 5.0 awd with a bad rear end. No big deal, existing axle was a 3.73 and had a pinion bearing failure, there was no lube in the rear end, probably cause of failure. I replaced with another 3.73 rear end and everything went well. Now my front axle case exploded, throwing the driveshaft into the fuel lines. I know the front axle was full of lube with an leaks. Are these axles weak behind a 5.0 or is there an underlying issue? I have not owned this very long and do not have any maintenance history. I purchased it for cheap on Craigslist so I know it will need some parts, but both differentials in less than a 1000 miles seems odd. Just my luck or is it pretty common?

 

I had a '98 4.0 SOHC 4x4 and had no front axle issues. My rear axle became a howler and was fixed under the Ford ESP. In my days of lurking here, and at another Explorer site, I do not recall an issue such as yours.

 

I assume you got a used one from a junkyard. Are you sure you got a 3.73 rear end as a replacement? Maybe someone swapped the gears. Now I'm paranoid about the rear end I got last year. The thought that someone might have changed the gears never occurred to me until now.

 

I would think a mismatch would show up right away with chirping tires and clunking etc, not a busted diff.

A 3.73 in front and a 3.55 in back might run long enough to wind it up good...

 

I've had over 20 explorers and only replaced 1 rear end due to a bad pinion and one front end for bad seals and it was cheaper to get a low mile junker axle then fix either.

Not common at all IMO

 

The rear tag on the new one is 3.73, same as the old. I will swap the front and see how it goes.