I just installed a set of Troyer e-fans. The controllers immediately failed, but I've wired them manually until the new ones come in. However, I have noticed that even running both fans, my transmission temps have gone up 10-20'F. I have an Autometer trans temp gauge (with electric sender mounted in the 4R100 trans body). With the mech fan, temps ran around ambient + 20 when sitting at idle. Now, the temp runs about ambient + 35-40. I'd like to install some 4" fans on the trans cooler. Thoughts?

 

I am not sure where the trans cooler is mounted on an Expy but my guess would be that the new fans have changed the air flow and the stock fan may have provided some flow to/over the trans cooler. I think your 4" fan idea is a good one.