Why Does My Transmission Fluid Look Milky? Here’s Why

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The reason why your transmission fluid looks milky is, that you have a leak in the vehicles cooling system or someone accidentally or purposely is sabotaging your vehicle.

Let’s think more positive and look at the most common cause of why your transmission fluid looks milky. That usual suspect is the radiator. Yes, I said it, your radiator just took a crap.

I am guessing your transmission is probably slipping too with all of that coolant inside of the transmission. I wrote a recent and more in depth blog post about how to diagnose transmission problems and repairing it on a shoestring budget if you need more help.

Why radiators are used as transmission coolers

Radiators are used as a transmission cooler source to cool the car’s transmission fluid because it makes for proper cooling by being right up front as the engine cools from this source also.

The manufacturer of the vehicle also uses the vehicle’s radiator because it is also a heck of a lot cheaper to just ad fittings to the radiator as opposed to giving every single vehicle that they produce a separate transmission cooler.

Imagine the amount of money the vehicle manufacturer saves by doing this, it’s in the millions of dollars. It works well for their pockets, but not for the better health of the vehicle. I HATE THAT THEY DO IT THAT WAY!

What happens when transmission and coolant mix?

The transmission was not built to function on the coolant and water. What happens next is the clutch material and seals begin to swell and causes the transmission to drive erratically. Rust also begins to form inside of the transmission which causes solenoids and switches to stick.

How to fix the problem

Giving if you caught the leak as soon as it happened and more than likely if you are reading this blog post today it’s probably too late.

The way to fix this is to rebuild the transmission with new parts. REMEMBER the seals and switches inside of the transmission is contaminated. Be very aware that transmission flush will not bring your transmission back to life.

If a repair shop recommends a transmission flush, they’re just taking your money and you’ll still have an erratic driving transmission.

You will need to get a new radiator but if your pockets are a little shallow, you can bypass the radiator and add an external transmission cooler.

How to prevent this from happening in the future

Some vehicles get lucky and this the radiator transmission cooler never leaks into the transmission. I do not know if you would want to go through the trouble of just bypassing the radiator transmission cooler on all of your future vehicles.

Seeing what it’s going to cost you to repair your transmission, I guess it’s worth the extra effort.