Back in the 70s when we were young and real poor, we would use an old A/C Condenser coil for a trans cooler. They were definitely on the large side and real cheap! We had no good way to check the temp, but it seemed to work pretty well. Anyone try this? I wonder just how efficient they really were?

 

I went with a buddy to look at an F600 with a swapped in 460/C6 combo and it had one of those home brew coolers. The old timer swore by it.

 

I would imagine that it would restrict the flow on the newer transmissions with larger 1/2" lines, but 5/16" used to be the common trans line size.