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Transmission fluid, should I or not

My radiator has a hole and have to add 1-2 quarts like every week and it seems to be getting worse.
It seems my car loses transmission fluid when changing the radiator so I will need to add like a quart trans fluid and my car is 200.000 miles and I have no idea when or if someone has ever changed the transmission fluid I bought the car with 155.000 miles on it and haven’t changed it.

So basically I am worried adding that 1 quart of trans fluid might destroy my transmission but I am not sure so what do you guys suggest I do, is there a chance it will mess up my transmission so I should just keep driving till the coolant leak becomes unmanageable or sell the car or just replace the radiator if there is not really a chance of my transmission dying from 1 quart new trans fluid.

Thank you all.

Adding transmission fluid as needed is critical. failure to keep the fluid level up to the minimum will damage the transmission. But also, if transmission fluid is leaking into the radiator via the cooler then coolant can enter the cooler and contaminate the transmission fluid and result in catastrophic failure of the transmission.

“A stitch in time saves nine” comes to mind here. If you get ti it before it’s too late and replace the radiator then drain and refill the transmission the Corolla might have another 50,000+ miles in it.

Don’t step on any pop tops.


You’re overthinking this. Replace the radiator before you overheat your engine and cause damage to it. Also note that if you’re leaving puddles of coolant on the ground then you’re killing any animals that drink from it.

I just asked if putting new fluid in a transmission with 200k miles on it would make it fail. My radiator is fine it just slowly loses coolant so I just have to refill it once in a while. No overheating etc.

No, if it was leaking that much I wouldn’t be able to drive without filling it everyday anyway.

That is what you wrote . Fix or replace the radiator . And I guess you are worried that adding new fluid to the old transmission fluid will cause damage . Doubtful if it will , besides this thing probably still has the original fluid in it and it could fail at anytime.

And I also don’t want that stuff on the ground .

Does it have a transmission dipstick? Or loosen a cooler hose.
Drip a little on a paper towel and inspect color.

No my car is pretty stupid it is 05 malibu no dipstick or anyway to check the color or even the level. My transmissions shifts smooth and doesn’t have like a delay or anything when I give gas. I will probably just keep it until it actually gets a big hole to make a difference then decide to sell or repair.

As I said in my first post: loosen a trans cooler line and catch a few drops.

Where is the radiator leak? Crack in a plastic part?
I once got stranded (as a passenger) in a Toyota minivan in the mountains of Jamaica when the radiator tank ruptured.
It had a crack that had been repaired before with JB Weld.

You are way overthinking this, just replace your radiator and stop wasting money on coolant. Just replace the lost transmission fluid with the right kind for your car.