I pulled a smaller 5er with an `02 GMC 3500 DMAX/Allison for 3 years. Ran great and I was scompletely stock. The reason I went back to Ford was my new trailer was heavier and the GCM wasn't cutting it with the taller rear (for some reason GM only wants to put 3.73's in). I needed more towing capacity.
John, Joyce and Zoie (our 17# Guard Dog)
2018 Ford F-450 KR / 2019 Mobile Suites 40KSSB4
Fulltiming since 2008 and loving it