Just got my 2005 H2 SUT!!!! ...FabTech lifted , RoadArmor front and back, 20" rims / 37"ATs ...just arrived in NC mountains home , Shooting Creek! ...a perfect trip: now to change all fluids to get it off to a great start ; ...all suggestions from others on your favorite fluids and additives will be appreciated... This is my first Hummer, formerly had 3 Dodge Duallie Diesels to tow horses.... This H2 is for luxury 4x4 fun ! I'm putting all Mobil 1 synthetic in engine ,has 160K on it now..… what's your favorite fluid for transmission???….full flush??? Do any of you add Marvel Mystery to your gas? ...it was great for our diesels...don't know much about 6.0l gas...?? ...and any experiences with fixes for the baffle (watching from driver to passenger on the AC )????....cold air going to passenger side only right now.... Is this an unusual problem??? Great to get other owners experiences and suggestions.... I'm one happy newbie!!

 

Welcome to HF

 

Quick update on my 2005 H2 SUT.....!!!! new Mobil 1 has myHummer hummmmmming.... any tricks or suggestions regarding tranny flush appreciated.... getting 12+ around town roads...??? unexpectedly good!!!??? i'm using regular gas....???....seems good, should i add some Marvel Mystery to fuel? really great on trails up here, unstoppable! i don't presently have a cover on the bed of my SUT... any good suggestions from experienced campers sought..... take a minute and say helllo

 

12 is incredibly good for around town. I'm guessing that will creep down though. I can get 12 on a road trip and it takes over a week around town for the average to slowly drop eventually settling at around 10.5 on mine. I've never put marvel in my H2. I did put it in my GMC (5.3 but basically the same engine) once many years back and it ran like crap so I never tried it again. We have an ambulance service and we do add some occasionally to the powerstrokes though (almost all are 7.3 ford chassis).

I do run synthetic (Amsoil) but have not had mine long enough that I've really looked at changing the diff, trans, and transfer cases fluids yet. I've checked the trans fluid and it looks new...

As far as the air being cold on one side and not the other. Make sure it is set to the same temp for both sides first of all just to be sure... If it is then you need to figure out which of the blend door actuators are acting up. Do a search for that on here.

One other important tip - a LOT more GM trucks are on the road. As such there is a LOT more info on troubleshooting certain things like engine, much of the electrical system, and more on GM truck sites. They have basically the same systems in many many aspects.

Welcome and nice looking rig by the way!

 

My SUT gets 10.3 round town.