4.56 gears?

[Hummie2]

One word of caution for anyone thinking about changing ratios "Check Parts Compatability for Your Model First".

I had one Bad Experience with GM products. GM likes to lock-up the parts market.

I order a 88 1ton Chevy Ext Cab 4X4 w/7.4L eng when they first came out. The rear axle for that eng was a Dana70, posi-trac was not a factory option. NO Problem, I'll order a "Detroit Locker" and install myself when truck arrives ...WRONG!

The truck arrived and I pull into shop @ work and pull out rear end gears and open carrier, mount gears and bearings on Det. Locker and go to install back in axle housing - WON'T FIT RIGHT. Nothing to do but put gears and bearings back on open carrier an reinstall in truck.

All Dana70's had been the same forever EXCEPT this run in the NEW Chevys had a different pinion gear offset. GM had a SPECIAL run made for this model so they could have EXCLUSIVE parts market.

BY GOSH I was going to have a Detroit Locker in there come HELL or HIGH WATER and I knew a good machinist that specialized in gear work. He built up and machined the locker to fit and it was a "one-off work of art" when he finished, but it wasn't cheap as he was very proud of his work. That thing worked GREAT when I installed it.

The only down side was that engine could drain a 32 gallon gas tank in 150miles when towing my off-road race car trailer. It would make the H2 look like a gas miser.

Moral: "CHECK FIRST" don't assume anything.

Don