2001 Outback 2.5 with 5 Speed
Very insightful post. I work for Napa Auto Parts and we see this kind of stuff every day. I am proud to work for a company that has just a little better quality control then some of the "other" after market suppliers. But I also agree with what you just said. Many times parts from other suppliers are the exact same part just re boxed and sold under their label. There are only so many manufacture's for a part and re boxing is how we get our share of the pie.I have never used a reman axle from Auto Zone. I have from other parts suppliers and have not had any problems.
What you need to understand about the parts business is that the parts companies buy products from manufacturers and sell them. Like a grocer. You find the same brand in all the stores, with slight difference in price or packaging. That house brand bread was actually made by Rainbow, just for example. Its the same blend, different package. The downside of Auto Zone is that they have a poor house brand across the board because the manufacturing specs are reduced in quality. Reduced quality equals reduced price. I do know that their electrical parts are poor.
Now, in comparison with OE parts: The auto manufacturers do not manufacture their parts. The engineers design the build for the part and contract it out to the actual manufacturer. Denso, Mitsubishi Electric, NGK, Bosch, Gates, to name a few, manufacture the parts then ship to the factory. Now, when you find that you can't get the part anywhere except the dealer, or get the one that actually works, it is because the Auto Manufacturer has locked up production and bought the rights to hold for a determined number of years, before that part can be offered in the aftermarket. That's why some aftermarket parts just don't work on a Subaru. They are not made to exact specification. Just close, not perfect. Until the production rights are released, the aftermarket can only make and sell inferior parts.
You ever get that part from the store down the street and the plug is slightly off? It wasn't an accident. That slight change allows them to sell it as a part that will fit, although incorrect. Same with the electronics, the resistance built within can be out by .001 and pass as a working part, but the PCM will see it different.
And the description about parts that are not exact matches is spot on. That's why an aftermarket thermostat is not exactly like OE (though our newer import brand is close to OE) And why my filter manufacture "Wix Filters" just released a new filter for our cars with the correct pressure by-pass valve. 23psi instead of 8-11 that they previously sold. There are a few others I'm forgetting, but luckily many aftermarket parts fit the 2nd gens pretty well.
Thanks for your OP and sharing your stories. I cant tell you how many times I get customers who come in buying up parts left and right trying to chase a problem. They end up spending way more money to throw parts at it then a simple diagnostic fee at a shop. I try to steer people away from that practice, but some people just have thick skulls or just are stuck in their ways.