Should be no pressure, the ATF is just pumped through the cooler back to the transmission.
12 to 14
The breather vent on a TH400 transmission is typically located on the top of the transmission case. It is a small, cylindrical fitting that allows air to escape and helps prevent pressure buildup within the transmission. Proper venting is crucial for maintaining fluid levels and preventing leaks, so it's important to ensure that the breather is clean and unobstructed.
The TH400 transmission typically requires about 12 quarts of fluid when completely filled. However, the exact amount can vary depending on the specific vehicle and whether the torque converter is included in the measurement. It's important to check the transmission dipstick for accurate fluid levels, especially after a fluid change or service. Always use the recommended type of fluid, usually Dexron III or compatible automatic transmission fluid.
You will notice two lines going to your radiator from the transmission. One is a service line and one is a return line. The radiator has a transmission cooler built into it. If you have trans fluid in the radiator chances are the trans cooler is leaking. A little trans fluid in the radiator will not affect engine cooling BUT as soon as the pressure drops in that transmission you may very well have radiator coolant sucked into the tranmission and that will ruin a transmission in a hurry. You need to get this checked out as soon as possible.
Via a pressure-driven transmission fluid cooler fed by in and out hoses near the radiator reservoir. They can be as small as about 1" x 1" x several inches and resembling the guts of a radiator, finned tubes; although they can get to radiator-sized.
1 and a half to 2 qts
The 2 lines that come from the transmission and go to the radiator are full of transmission fluid and the radiator is what cools it.
You replace the radiator
"transmission fluid leaking from fitting below radiator cap after replacing radiator on 99 surburban
Fluid Connector
No. Transmission fluid lubricates the transmission. Coolant is used by the radiator to cool the engine.
This is transmission fluid. The leak is at the transmission cooler which may be part of the radiator.