Jim Grant's Tech Tips
Chevy Pick-up, Water in the Transmission and Oil Coolers
Q: How can water be getting into the transmission of myí89 Chevy Pick-up?
Iím told that it could be coming from the radiator. Can the radiator be
bypassed and an auxiliary oil cooler be installed? What brand of cooler
and size for anĎ89 Chev 350- 700r4 4x4 truck short bed do you recommend?
vehicles manufactured with an automatic transmission use a transmission
oil cooler that is mounted inside of the radiator. The transmission oil
is circulated through this internally mounted cooler to reduce the transmission
oil temperature. Itís sort of surprising to think that hot engine coolant
would cool transmission oil. But the temperature difference of hot transmission
oil to engine coolant is great enough that it does remove heat from the
transmission oil. Which is okay at best. Unless youíve been driving your
vehicle in way too much water, then about the only way water/coolant could
enter the transmission is through the radiator mounted transmission oil
cooler. You can by-pass the cooler in the radiator. But in your case you
are going to have to plug the cooler. Before doing that it will have to
be rinsed thoroughly of transmission oil. After all if coolant is getting
into the oil cooler, then the oil in the cooler can get into the coolant.
If you want real cooling system problems just have a little transmission
oil mixing in with the coolant. That combo will eat the coolant hoses
up like there is no tomorrow. As for transmission coolers they are a great
add-on to extend the transmissionís life. Deciding which transmission
cooler would be best for your vehicle is relatively easy. The manufacturers
have an application chart that will direct you to the correct size cooler
for your vehicle.