2005 subaru transmission replacement

I need someone’s opinion. Two months ago, I took my 2005 subaru forester into the dealership shop for what they refer to as an “Intermediate Service”, recommended every 15,000 miles. On top of an oil change (which is what I initially went in for), they checked all other fluids. They gave me a Multi-Point Inspection Checklist afterward. On this Checklist they listed that my transmission fluid had “passed inspection”. They also noted that in the column representing “Inspection for Visual Leaks”, that LEFT H/G LEAKING AT 1.5(OIL) RIGHT H/G LEAKING AT .5 (OIL) OIL COOLER O-RING LEAKING AT 1, with a hand written notation “just minor”.

Fast forward to Christmas day, our “check engine light” goes on, and the car has a hard time making it up the hill to Grandma’s house. It felt like it was losing compression. I got the car in two days later ( we did not drive the car further after getting home that day). After inspection at the same dealership shop, we’re told the transmission is shot and we need to replace the head gaskets as well.

Question, isn’t condition of transmission fluid an indication of the transmission’s health? If the fluid was fine two months ago, can it deteriorate so quickly? I’m questioning how this big problem was not caught during an inspection two months ago.

Comments would be helpful.
-Cara

This is an automatic transmission I assume. Visual inspection of the fluid does not mean much at all unless the fluid is dark in color and smells burnt. In a case like that, trouble is brewing. The inspection was likely a quick look to make sure that it was full and one would hope that if the fluid was dark, etc it would have been notated.

If this is an automatic trans, there are actually sections of the transmission that require different fluids.
One is the auto trans that uses the normal ATF and the other is the final drive section that uses hypoid gear oil. The final drive section often gets overlooked when being checked.

Another potential problem area is that the oil drain plug on the final drive is similar to the oil drain plug on the engine and they are located pretty close to each other. A number of Subaru transmissions have died because someone (usually someone not familiar with Subarus or a novice lube guy) inadvertently drains the final drive by mistake instead of the engine oil.

Sometimes this is caught and corrected and other times it is not. What i would be curious about and what you need to determine is if the final drive is low or out of oil and/or whether the engine oil level is overfilled.

That’s about the best I can do without car in hand and filling in the blanks. It could also be that if the trans has high miles and has never had the fluid changed previously it may be on the way out. Knowing what codes are related to the CEL coming on could also help in least formulating an internet guess.
Best of luck anyway.