[HUMMERcustoms.com/TAZ]

I would agree wth usng the 6 over 3 if manual calls for it and you are running stock equipment. None of the factory oils are going to take extreme use situations like allot of desert running off-road and in my case extremely high HP and torque. I spoke with engineer that said with my application that regular OEM rated oils would fry in my tranny and other equipment.

If it is town use with occasional off-road or mudding as long as You are getting plenty of cooling should work for most all Hummer users. But, as mentioned by a few other guys the performance grade oils will help with smoother operating, lower temps, and a little HP increase as proven in a test on HP TV show on Spike. Switching to Royal Purple after a dyno run with a camaro with new factory fluids and filters the car was changed again just like before factory fluid runs and when replaced with all Royal Purple the car was dynoed again and it gained 8HP and more torque. They were just showing the gains that even just a regular street car could get and even recommened extended fluid changes as suggested by Royal Purple. In a lightly used street ride I would most likely go with extended recomendations to make cost equal out. In heavy use rides I would change more frequently.

TAZ