Ok so I did the research and crunched the numbers and it makes much more sense to me to have a 4.56 gear ratio with a true 35 inch tire. I run the BFG mud terrains so they are pretty close. My normal Highway cruising speed is around 70MPH but most of my driving is under 40 around town. I am personally convinced I would get better fuel economy and a little lower crawl ratio off road. Also I am considering a lift and 37s down the road. Any thoughts on this or has anyone already made this upgrade? And which brand of gear would be best for the GM axles?

Couple of thoughts...

I put 4.56's in mine with 38's. Mathematically, 4.56's are the same ratio with 38's as 4.10's are with the 33" height OEM tires (yes, I know they are considered 35's but they really measure 33")

That being said, I wish I had gone with 4.88's so I think going with 4.56's on a set of true 35's will be perfect.

I know I didn't hear it from some of the other guys but when I put the 38's on, my gas mileage dropped from 10.5-10.8 to 8.6 average.

I installed the gears and it's back up to 9.6 average.

As far as gear brand, precision gears are decently priced and are decent quality. I won't go with zoom gears EVER again.

Give 4WD Parts a call and ask them which brand (I think it's called Genuine Gears) gears they sell that have a lifetime warranty. They warranty them whether they are installed incorrectly, break, wear out, anything... they are warrantied for everything for lifetime. (plus they are the lowest price I found)

HTH's,

Mark

Whenever I have done gears, my choice has been the OEM units. Yes, some/most are made from an outside source, but the quality control seems better when in a OEM factory box. Methinks GM makes the size gear your looking for. Be sure to change the crush sleeve/pinion seal and ask th eparts guy what additives go into the rear.

Thanks for all the comments and insite. I'm going to hold off on the swap for now. I just ordered a Hyp III programmer to play with my shift points a bit. I did a search and found lots of useful set ups using that exact programmer. So far I'm 100% happy with my H2 going on 3 years and 33000 miles. Nothing to brag about yet but I still grin everytime I get in..later dudes...Happy Easter...Oregon OUT!