We sell transmission fluid for Fuller Roadranger transmissions. Schaeffer #744 is a synthetic gear lubricant SAE 40 and Schaeffer Super Lube Supreme SAE 50 (#239S) a premium quality para-synthetic fluid. These are both premium quality lubes although the #740 being fully synthetic complies with the Eaton approval on their 750,000 mile warranty. If still under their warranty please choose #744 so as not to void the warranty.
If your transmission (pre 2015) is outside the Eaton warranty you can save some money and use the 239S SAE 50 Super Lube Supreme. You will not notice any difference other than the change interval will be slightly more frequent. Both of these lubes have the same Schaeffer quality additive packages that set Schaeffer's lubricants apart from all the rest.