Last month I installed a set of Flex-a-lite 290 fans in my 2002 Silverado HD (8.1 with Allison). Also installed a 160 thermostat to help keep things cool. The temp gauge stays in the 180-190 range unless the truck is idling for awhile. Then it will go up close to 200. This is the same with or without a trailer. The trans temp will usually stay in the 160-180 range when the truck is unloaded but will climb into the 210-220 range while pulling. This has just been done with a 24' boat and car hauler with a mix of highway and backroads. I haven't taken any road trips with it to see where the transmission temp stays on the highway but from what I've seen it runs higher than with the mechanial fan. The used to be in the 190-200 range. I'll post more info after I do some long highway towing.

Tom