Hello,

I have:
91 F250 351W

Last summer I bought and installed an extra transmission oil cooler (because it was cheap and I wanted a little project).

What is the best way to install these things? What I did was route oil from transmission into radiator cooler, then from radiator cooler to external cooler, and back to transmission. So it goes:

1. Transmission
2. Original Radiator Cooler
3. External Cooler
4. Transmission

Is that the best way, or is it better to reverse 2 and 3 like this:

1. Transmission
2. External Cooler
3. Original Radiator Cooler
4. Transmission

I'm probably going to be taking things apart this summer due to not liking the look of where I mounted it, so I'd like to re-install in the best way.

Thanks!

 

How about this,
We would like to keep the trans operating temp as close to "operating temp " as possible.
If we choose the first path you mentioned the red temp should be in the area of 140-180 degrees F.
I never measured the temp of the fluid coming out of the rad cooler, but some vehicles did have a gauge showing the temp.
It probably would be a good idea to measure both set-ups and see which provides the best cooling.

 

You should go through the radiator first, then the cooler.