Cooler help

Jerry Little

Member
Original poster
Joined
Jul 28, 2018
Messages
73
Location
San Jose
I'm installing a new transmission and tranny cooler should I bypass the radiator all together and only through new cooler? Or both? The cooler is for 29,000 gross vehicle wieght and I don't live in cold weather or snow
 
I would keep both. The radiator cooler will help keep the transmission temperature more stable. Transmissions are designed to operate within a certain temperature range. While rare, overcooling can be possible. It won't cause severe damage or anything, but the fluid will be a different viscosity than the manufacturer expected and may not lubricate as well, resulting in marginally shorter life.

Another way to look at it is with your aftermarket trans cooler you can add marginal cooling power to the coolant system because the flow of heat in the heat exchanger is reversed.
 
I'm installing a new transmission and tranny cooler should I bypass the radiator all together and only through new cooler? Or both? The cooler is for 29,000 gross vehicle wieght and I don't live in cold weather or snow
Keep the ATF flowing through the OE cooler in the radiator, connect the aux cooler to the output of the OE cooler. Some will disagree with that but the major transmission cooler manufacturers like B&M and Derale recommend connecting an aux transmission cooler in the output side of the factory cooler.

Transmission cooler diagram.webp