The AISIN is indeed a separate company from Allison. I have a Ram 3500 Cummins and absolutely love the truck, I have had zero issues with it and has proven to be a very reliable workhorse. I have towed a TT with it and now have a big heavy truck camper, which the truck handles very well. Basically any of the big three are capable enough to do the job, but know that Ford has had some serious issues with their diesels over a few model years you may want to investigate. There is a business in Mesa, AZ (sorry forgot the name) devoted to making and installing the failing components on Ford's newer generation diesel trucks. Ford had a good diesel engine up to somewhere about 2000 or so, then for whatever reason, messed around with a good and reliable design, which created a host of pretty serious problems. That steered me away from Ford at the time I bought my truck. Perhaps they have worked them out by now, but I know of two owners with 2011's who were having significant problems. Ram's Cummins diesel and Chevy's Duramax are tried and true power plants and they have for the most part stuck with a winning formula. The Aisin tranny on the Cummins and the Allison tranny on the Chevy/GMC are very good tranny's, the best in the business. If I am not mistaken the Allison is included on all Chevy/GMC trucks while the AISIN is only available on the 3500 Ram's and is an option. If you opt for the Ram, I would definitely opt for the AISIN. If you opt for a Chevy/GMC look verify if they come equipped with the Duramax.