Which should I fix first?

I recently inhereted (OK, bought for dirt cheap) a 2000 Subaru Forester. After looking it over, I discovered it needed a few things, including a new transmission and a new catalytic converter. I’ve saved a lot of money by getting the car for the price I did, but not quite enough to do both repairs right away and I want to know which one I should do first?

The transmission works except for the fact that it doesn’t readily go into drive unless you wait a bit for the fluid pump. My mechanic also noted that it is beginning to bind a bit in the rear. The catalytic converter is affecting the gas mileage of the car but is otherwise not an impediment to driving it.

If you had to choose one repair to do first, which would it be and why?

Thanks for the help.

I’d do the cat first. And here’s why.

If the cat is restricted, it creates backpressure on the engine. This backpressure can cause the engine to run hotter. If the engine runs hotter, the coolant temp runs hotter. The transmission fluid is cooled by a heat exchanger within the radiator. If the coolant is running hotter, it removes less heat from the transmission fluid. And this causes the transmission to run hotter. See the domino effect?


Thanks, that is exactly the info I was looking for.

What I would like to know would be if the Check Engine Light is on and how sure are you or how you determined the converter is responsible for any gas mileage drop.
If the trans is slipping that could be the reason for a fuel mileage drop; for a short time anyway.

Have you priced new or rebuilt transmissions for Subarus? Cheap they are not.

Are there other symptoms that will point to a bad catalytic converter, other than a higher than usual engine temp? Especially on older cars that don’t have a CEL.

It’s a 2000 car. It has OBDII (actually, every car sold in North America since 1996 does). Therefore, there will be a code stored and able to be read, if the CEL is on.

I know. I’m asking for general symptoms, and for older cars without a CEL or OBDII, like I said.