I bought a '97 Subaru Legacy Outback Wagon about 2 years ago from a friend. I’m the third owner and the other two were my friend and his father. It currently has 121K miles on it. As soon as I got it I replaced timing belt, oil pan, all 4 brakes, links/bushings, an automatic window mechanism that failed on a rainy day, wheel bearings, and some other small stuff. I paid $1.5K for the car and the put another $3K into within the first 6 months, so I felt like I was driving something safe and worth pretty much exactly its blue book value. I knew from the start that I would eventually need new rear struts, but it wasn’t urgent, and my mechanic has been encouraging me to put off fixing things until I absolutely need to because the front differential gear makes some noise. He said I would know when it was starting to go because it would get much noisier, and up until today, the sound has been about the same, but we talk about this whenever something small needs fixing, and each time I ask “is it worth it, or will the differential gear go before I’ve paid it off on my credit card?” He usually advises that if it is expensive and not dangerous, it can wait.
Last week, I brought it in because it had been leaking oil badly after a recent oil change. He found that the crankshaft seal had become loose and oil had gotten all over everything–including the timing belt. He also determined that the struts could not go unrepaired any longer. I asked if this was worth fixing in light of the state of the differential gear, and he advised that I should replace the crankshaft seal and the timing belt if I ever wanted to drive the car again, and that the struts were no longer safe. This work was going to cost $1.3K
I had known about struts forever, so wrote that off as an expected expense, and (though this did not pan out in the end) I had a hope that I could get the company (let’s call them “Valvoline” for the sake of of discussion) that performed the oil change to take financial responsibility for knocking the crankshaft seal loose, so I approved the repairs. The mechanic held on to the car A LOT longer than usual, and was much harder to communicate with than usual, but the repairs were done by the end of the week. I picked up the car, drove about 30 miles in it over the course of 24 hours, and then the differential went. I can’t afford to repair it, even though everything else on the car is in great shape.
So here is my question: Would the mechanic have been able to tell by looking at it that the differential gear was on it’s last leg? Is it possible that he could have looked at 24 hours before it went and NOT been able to tell it was about to go? Did he know, and encourage me to spend money on something that was about to die, or is there no way that he could have known? I’m not sure there’s anything I can do at this point, but I’d like to know how trustworthy this guy is for future reference.