H3 Specs


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Picking up from yesterday when I discussed how I’m really interested in buying a Hummer H3 to replace my Jeep and that I’m excited to run down the specs of the H3 today is because of all the things I will not have to modify on the H3.

So beginning with a bit of a history lesson, the H3 Hummer is a crossover SUV from GM in 2005 based on the GMT355 platform that it shares with the Chevrolet Colorado and GMC Canyon compact pickup trucks. Originally equipped with 3.5L inline 5 cylinder motor (220hp and 225 ft·lb) the motor was considered underpowered and quickly replaced with the 3.7L inline 5 cylinder motor (239 hp and 241 ft·lb) in the 2007 models and newer. As the quest for power wasn’t enough, the model “Alpha” was produced with a 5.3 liter V8 producing 300 hp and 320 ft·lb of torque in 2008 and up. The 5 cylinder motors come with 4.56 gears from the factory whereas V8’s get 4.10 gears factory. Equipped with a 2-speed full-time four-wheel-drive transfer case, 2.64:1 gear reduction for standard H3’s and 4.03:1 gear reduction for Off-Road editions,  your options are “Four Wheel High,” “Four Wheel High Lock,” and “Four Wheel Low Lock.” The factory tires are 31 inches unless you get the “Off-Road Suspension” or “Adventure Package” which in that case you have 33-inch tires factory and a rear locker (and a front locker if newer than 2008). Finally, the gas mileage is 16 city and 20 highway, and the wheelbase is right on the magic number of 111.9 inches (A wheelbase of 110 inches just seems to be perfect in the off-road world).

Now lets race down the similarity of my Modified Jeep and a Factory 07 H3 with the I5 and Off-Road Suspension Package.

  1. Both have inline engines for durability (H3 motor is more powerful)
  2. Both are running 33-inch tires
  3. both can have 35-inch tires put on them
  4. I wish I had gotten 4.56 gear but I got 4.10… the hummer has 4.56
  5. Same wheelbase length (love that magic 110 inches)
  6. Both AWD but my Jeep has 2 wheel drive after an expensive swap
  7. I have Limited slip in both my differentials, the hummer has a Full locker in the rear (fair trade if you ask me)
  8. Gas mileage is the same
  9. the same seating arrangement
  10. Height of both are approximately 72″

Now the differences

  1. I have solid coil-sprung axles front and rear (more flex) the hummer has independent front and a leaf-sprung solid rear axle (steers better)
  2. My spare tire is inside the cargo area (I hate it) the hummer can fit 35-inch spare tire on the rear door factory 🙂
  3. Ground clearance is where the H3 losses. I have 17″ the hummer has 10.5″ but an easy fix
  4. The H3 has a wider stance at 74.7 and the jeep is 70.9

With all that listed it really gets me because of the time I wasted getting my Jeep to that point only to be trumped by a factory H3 Hummer. Other things I have noticed is how much stronger the door hinges are, more durable the frame is, and how much better handling an H3 has over my Jeep.

With that, I end today with even more excitement then yesterday to write about the parts I want to upgrade the Hummer H3 with and have the words “Less is MORE” in my head.


  1. Hi, Wow what a great comparison.
    I’m getting myself a H3 3.7 litre Adventure. I drove it and I love it. There is one thing I’m not too sure about how do I know if my hummer will come with a diff lock at the back? And how will the dash board be different from the H3 Luxury.

    1. First, just to provide absolute certainty to anyone out there, a H3 Hummer has to have a Differential Lock (Diff Lock) to have the Adventure Package, otherwise it is just a standard H3 Hummer.
      As for that diff lock button, the red arrow is pointing at it. Also note that because my H3 was made in 2006 I only have a rear locker, where as the 09+ models have two of those Locker buttons and the Traction Control Button is relocated else where.
      H3 Hummer Differential Lock Button

      1. Sam Vance Avatar

        I have the 06 H3 luxury edition. Is that considered a base model with leather seats and chrome? It also came with 265/75r16’s instead of the 285’s. It doesn’t have the rear locker either. My question is, does the luxury have 4:56 gears, why does it have a full time 4 wheel drive button then two more 4 wheel drive buttons with locks on them? I know it doesn’t have the locker. Can someone please reply? Thank you

        1. If you have the inline 5 cylinder engine you have 4:56 gear, if you have the V8 engine you have 4:10 gears. You’re Hummer doesn’t have a locker, what you looking at is the different options for the transfer case. The option are 4×4 Hi, 4×4 Hi locked, and 4×4 lo. Don’t use 4×4 Hi locked on paved roads unless is completely covered in snow. I recommend visiting http://www.hummer4x4offroad.com/ and becoming a member, you can learn so much from those guys.

        2. Hi,
          I have a 2007 H3. I don’t know if I have the Luxury Package or the Adventure Package. I have the orange lights on top. Leather, sunroof, heated seats, monsoon stereo, chrome door handles, chrome running boards and the rear diff locker button!
          Thank you!

  2. Hi Nice comparison that I wish I had read before buying my H3 Luxury. The adventurer would have saved me a fortune in diff locks and diff rebuilds. I was interested in your comment on ground clearance being an easy fix ? 2″ lift sure its easy but lose downward travel in the front. To get to the 17″ of the jeep is a massive undertaking that costs big bucks like SAS. If you have another method I would love to hear more about it before making my mind up between SAS and Rancho lift ?

    1. You don’t lose any travel up front. The bolt is tightened and raises the resting point, which I recommend because a factory H3 Hummer sits on the bump stops. I find the ride quality to be much smoother once this is done. I recommend skipping the SAS or Rancho lifts for a bit, try cranking the torsion bars and a set of my extended shackles with leaf spring mounts, buy a set of 35 inch tires and taking it off-road. The lift will only cost $300 and you can return the vehicle to factory if you decide it’s not for you.

  3. I have a 2006 H3 Luxury with 265 tires. Can I go to the 285s without reprogramming the computer? If I am only going to be running mountain fire trails is this upgrade worth the price in equipment and fuel?

    1. 285s completely fine on your h3, shouldn’t notice much difference on the speedometer. However, I recommend going to 315’s, the make the hummer look much better and fit fine with out any issues.

      1. I read somewhere that most tire installers won’t put 315s on stock rims. Is this true?

        1. I went to “Discount Tire” and had them put my 315’s on my Hummer’s stock rims without any issues. For off-road the rim size is absolutely perfect with tires that size. The installer told me it might not fit, but I assured them that it will. Ever thing went smooth and I have no issues since then.

          1. Thanks for your advice.

          2. No Problem. Would love to see photos when you get the new tires!

          3. Eric, I went with the 285s. Cooper Discoverer AT3s. Couldn’t be happier. 35s look bad asks but these will be better for our everyday use. What a difference they make.
            Really enjoy your site.

          4. I went to 285 on my H3 as well. Wish I knew how to upload pics on here from my iPhone. I bought Dakota Definitys made by Cooper for $821 mounted and balanced at Pep Boys.

          5. Eric, after installing the LT 285s, the handling over rough reading i.e.. a patch of poorly filled potholes, the steering seems to skip a bit. Movement in steering wheel. I didn’t. Notice this with the P 265s. Maybe I just didn’t encounter the same condition. Is there anything you would recommend checking. H3 only has 65000 miles on it.

          6. Can you fit 315’s with no lift or level?

          7. Schwarttzy Avatar

            Yep, I ran 315’s on stock ride height for months before lifting my H3 Hummer.

  4. Justme Avatar

    You said your modded Jeep is running 33’s and you have 17″ of ground clearance. How are you coming up with 17″ ground clearance while running 33″ tires?

    1. I wasn’t counting the axles.

      1. Justme Avatar

        Ok. That makes sense. I appreciate the response. Thanks

  5. Hi, I’ve been searching and searching for a answer. Can I use a chev truck transfer case on my hummer h3? Or a gmc one? It’s a 2006 awd

    1. I wouldn’t know anything about that, just found the files and host them so other people can use the files.

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