Why Does My Transmission Fluid Look Like A Strawberry Milkshake?

Baltimore Maryland Transmission Shop

Because water or engine coolant has entered your automatic transmission and mixed with its fluid. The next question is, how did it get in there? And the answer is, from your radiator or a flood.

Is a gamble because the water may the two sources of water, the radiator is by far the most likely source. Automatic transmissions produce a great amount of heat and must be continually cooled. That is accomplished via two cooler lines that carry the hot fluid to the radiator and once cooled, sent back to the transmission. The fluid is cooled inside the radiator in a separate heat exchanger called a cooler tube which is made of brass. The transmission fluid circulates through it, is cooled by the engine coolant and then sent back to the transmission. If that cooler tube develops a crack, one of the following three things will result:

  • Engine coolant will be forced into the heat exchanger and then sent back to the transmission.
  • Transmission fluid will leak from the heat exchanger into the radiator where it contaminates the engine coolant.
  • The transmission fluid and coolant will contaminate both the transmission and radiator turning fluid and coolant into a strawberry milkshake

The course of repair will depend on how long the coolant has been in the transmission. No matter what else you do, the leak has to be stopped by either replacing the radiator or installing an auxiliary transmission fluid cooler. Next step, if the contamination just occurred, will be to flush the transmission using new fluid in an attempt to remove as much of the contaminated fluid as possible (it is relatively impossible to replace 100%). It is important to know that the damage to your transmission may have already occurred and this step is a "gamble". The coolant may have already started dissolving thehopes the water based glue that bonds the friction material to the clutch plates or rusted other parts. If the damage has already taken place, rebuilding or replacing the transmission will be necessary.

The other source of water in a transmission is a flood or high water. The water has to be deep enough to enter either the transmission's vent or its fill tube which means half way up the side of the vehicle.