T-400 lines

[madcarson]

I'm going to install braided lines for tranny, do I have to go into rad cooler also or is B+M ext good enough with deep Alum. pan?

[MonzaRacer]

if you drive year round run it through the external cooler THEN through the rad. Too cool is as bad for trans as too hot. Big cooler gets the heat out then the rad gets it back up to proper temp.

[GetMore]

This is a subject that does not seem to have a right answer.

Some people do as MonzaRacer have mentioned, for the very reason he gave. The coolant temperature at that end of the radiator should be at least 20 degrees lower than the engine temperature, since the coolant is supposed to be cool enough to lower the temp of the engine. So, you are probably talking somewhere around 150° and that is a good number for transmission fluid.

Some people believe you should run it through the radiator and then the external cooler. (By the way, this is how GM ran the coolers on my '01 Silverado.) This makes sure the trans fluid is not hot. I've never had my transmission do anything weird during the winter with this setup, and lots of people in Canada get by with their trucks like this, so I don't think it can be too bad.

The third option is to just run a good external cooler and not mess with the one in the radiator. This theory fits somewhere between the previous two, and I would think it's got the same problems and advantages of both of the previous options.

I don't think any of those options are wrong for you.

However, if you were in Southern California I would not use the external then internal method, since it almost never gets cold there.