Car Maintenance - A Necessary Evil

I drive a Subaru. I love my car. It brings me joy. I had never really realized it, but my wife told me the other day that even in the midst of horrible traffic, and stupid drivers, I look at peace when I am driving.

I do everything I can to do my own work on my car. If at all possible, I do it myself - oil changes, transmission fluid changes, tire rotation - I've even changed the timing belt: something I have been forever fearful about doing because of how bad it would be if I did anything wrong.

Several months ago, I noticed a noise that I hadn't hear before. I was driving into a parking lot, and was told that I was not where I wanted to be, so I reversed out of the lot, and heard a 'thunk', and since then, a ticking noise as I drove. It sounds like it comes from the right fender-well, and from the passenger's side, it sounds like it comes from the left fender-well, so it seems to me like it is coming from the front of the transmission. Rather than being in one gear, or changing the speed of repetition with engine RPM, it is directly related to speed, and occurs in every gear. So, in doing a bit of research, and asking around a bit, it seems to me like it is coming from the front differential - a diagnosis confirmed by a general inspections from two different transmission shops.


In diagnosing this myself, I've had to learn a bit more about my car. I found the gear ratios for the transmission, and did some quick calculations in Excel to see if the frequency of the noise related to anything in particular, and how the transmission is constructed to see where noises can be located, and what might be causing them.


But this being a transmission issue, there are several things that are preventing me from doing the work myself. First, is the lack of a proper workspace where I can take things apart, make a mess, and not have to worry about offending people, or having to secure my property before I turn my back every time. Second is the lack of knowledge about transmissions, and I know them to be something that you don't want to leave to chance.

I saved my pennies, and arranged with a decent shop, and took my car this morning to get my transmission fixed.

Ignore the rental car issue - whatever.

Got a call that the transmission is apart, and it's not what we thought it was - it was gears.

Crap. The spendy part. I couldn't walk there fast enough.

I showed up to review the damage, as he promised he would let me do, and he said that the gears for each of the forward speeds are fine, as is reverse. The front diff is... immaculate. o_O

Problem turns out to have been a snap ring on the center diff that partially came out of its groove, and when I reversed at the California Science Center for the Endeavour title transfer to find parking, it poled part of that snap-ring out, and that's what was ticking against the case with every revolution (literally like a card sticking out of the spokes, slapping against the fork of a bicycle). There have been two instances since where while backing up, there seemed to be a sort of 'diff lock' - a binding of sorts - but it was unclear if it was front back or center: I always presumed front because that's where the sound seemed to be coming from. These appear to have bent part of that snap ring back upon itself, breaking some of it off. Those broken bits found themselves in between the teeth of the gears that send power to the front from the center diff.

The good news: There's no labor in replacing these gears, as you don't have to disassemble a whole stack of gears. Obviously, of one is damaged, the other will be damaged by the one, so they both need to be replaced, but replacing them is easy now that the tranny is all apart on the bench.

I use a special mixture for transmission fluid, and have for several years. I do this on the suggestion of a transmission specialist on one of the forums that I frequent for Subarus, and often worry that some straight-laced shop owner is going to get uptight about speculating as to the reason for things breaking, and odd wear, and declare that he knows all, and that this mixture of fluids is going to cause the world to spin backwards, and it's going to spawn the antichrist or something, but no - this guy was impressed with it's 'tack', and even his father who has been in the business for many years before him was impressed with what it did, and the condition of the parts inside the box.

The owner said that my car was nice and clean, and that he was very impressed with how well it has held up to the 160k miles that I've put on it (well, just short of..), and the interior components of the transmission all looked to be in very good shape - forks look clean, and show no signs of abuse, damage, and hardly any wear. He said that it is unlikely that if I keep this up, that I will ever have to worry about the transmission again. He was so impressed with the fluid mixture that I used, that he said that he wanted to put that back in it, and really was curious as to what it was, and noted that he may start to use it in the manual trans jobs that he gets because it sticks to metal far better than anything else he ever sees (and that fluid was old - in need of replacing 7500 mileas ago): When he takes apart another transmission, the oil is nearly drained from the parts in about half an hour - this case was open, and parts were WIPED OFF, and an hour and a half later, there was pooling of the oil on the gear teeth still 'stuck' to the metal.

Shop owner says that if he can get the parts by tomorrow morning, I should be able to drive it away tomorrow afternoon by close. I say not bad for a transmission rebuild. I hope he can do it - I can't wait to have my car back.