Bypass radiator/tranny cooler combo?

Turtle n Peeps wrote:

LarryJM wrote:
Bypassing the OTW cooler in the bottom of the radiator is the worst thing you can do for maintaining tranny temps especially when towing. It it always the first cooler that the hot tranny fluid goes thru since it is the one that can extract the most heat due to the temp differential and is not dependent on the speed of the vehicle like the OTA cooler is. You examples of light weight non towing vehicles and any comparison of turbo intercoolers is comparing apples to oranges and IMO your worries about cooler failures is basically not founded on any data or reliable reports I have ever read.

Even the gaggle of engineers at FORD failed to appreciate this in the original design of the SD series when all they initially had was the OTA cooler and started loosing trannys from heat especially for those who were towing. They had to put out a service bulletin to replace or add the OTW cooler in the bottom of the radiator to solve the issue.

My recommendation is not to MUCK around with the engineered design of your OEM cooling system and definitely DO NOT bypass that OTW cooler in the bottom of the radiator if you want to keep your tranny.

Larry

Well said Larry.

OP here's the deal. You don't want tranny fluid too hot OR too cold. Most people on here concentrate on the too hot part and not the too cold part. Running it through the radiator is a good way to get the fluid just right.

absolutely correct. And I'll add. I have totalled 1.2 MILLION miles on 8 vehicles with automatic transmission all with cooler that go through the radiator. Number of cases of transmission cooler failures is ZERO.