Supercharge or gear swap?

[ASTAR]

Screeper, what did the gear swap cost you and who did it? Is there a carrier break to go to 4:88's (did you have to use new carriers)?
How bad does the mileage drop off after 70? I drive I-5 a decent amount and 70 is the limit. If I drive 70, I get run down by big rigs!
My good ol Dodge, cruising at 90 on 5 and getting 16mpg.
Oh well, the Hummer is like nothing else!

[Screeper]

I dont remember the cost right now but it is on this forum somewhere from when I actually had the job done. It was very reasonable and phil will give you great price on the gears and also make sure you get the right ones. All you have to buy are the gears and a bearing kit as they are bolt in. As for driving over 80. I just went to Orlando and was in more of a hurry then worrying about a few bucks. I think I had the cruise set at 85 and was getting 9.0 going into the eights on the small inclines they call hills down here. I know my avarage for the whole trip was 9.5.

[ASTAR]

With the cruise set at 85 does it stay in 4th gear? Mine will not hold 4th with cruise going over 75. Barely holds doing 70. And the mileage is horrible doing 75-80 (like 7-8mpg) in 3rd gear!
Why did you not put 4.56's in it? I think that would bring it closer to stock, no?

[Screeper]

I spin 2500rpm at exactly 80 mph. I am curious what a factory H2 is spinning at the same speed. I wanted to do just a little more then stock to increase the torque getting to the road and offset the weight of the rims and tires. Around town its better then stock. As I said before at 75 it cruises perfect with decent mpg. I guess at 85 mph on 38X15.50 tires I should not complain about 9.0 mpg. Your down shifts sound like they are being caused by the engine revving to low and needing to get back up into its torque curve. I think there are some people on the forum who did the 4:56 and wished they had just gone to the 4:88s. The difference between the factory 4:11 and 4:56 is not that great.

[ASTAR]

Cool, thanks for the reply.
Yeah, the truck just can't pull a decent speed in 4th with these gears but if it goes to 3rd, it holds whatever I want, the mileage just suffers immensly!
I'm going to go with 4.88's then. Now to find a good shop locally that I trust to do the job!

[Screeper]

Good luck. I think you will be happy. Feel free to PM me if you have any questions.

[mowdoc]

Hey Screeper,

I checked this morning and my stock 06 was turning 2300 at 80 mph in 4th with the converter locked.

I doubt I'll ever go to larger tires but if I had 38s on I would be looking for 4.88 gearing. I think anything less would be too much load on the tranny.

I have considered getting the Maggie blower but am waiting to see what other problems develope after supercharging is done. It would sure be nice to drive up a grade and keep the damn converter locked. I love my H2 but GM needs to take a closer look at shift points and downshift requests on this rig. I was spoiled by a maxed out DuraMax diesel before the Hummer and I tow a lot. The D-Max would pull a hitch in half in 5th gear while this Hummer can't pull itself up a slight grade without downshifting. Like I said, I was spoiled by the diesel. I do love the Hummer, I just wish it would stay in high gear more.

mowdoc