So my Jimmy is now on 31s and has 3.42s. With the 3.06 1st gear that's not horrible, but I am used to more off the line and prefer to be a bit more in the torque band.

It's nothing I'll do tomorrow, but I'd like to run 3.73s. I have a ring and pinion for the rear on hand (we have 2 4th-gen f-bodies and another S-series in the family). I know nothing about the front diff on these things. How hard to change gears on it and where do you get 3.73s for them...?

My wife's suburban has 265/75-16s (~32") and runs 4.10s and it works good, but can spin easily in the slippery stuff even with it's 7,000lbs of blubber. I'd not want to go that far. I think 3.73s would be about right and if I remember right it's the standard issue for the ZR2s...

So.....has anyone done this....swap the front diff gears to 3.73s...? Where'd you get them..? How much of a PITB was it...?

Also....who has got aftermarket axles for their 7.5...? We've gone 11-ohs on a 7.5 torsen using factory axles with a cap girdle and arp studs, but that isn't with a solid locker on a 5,000lb truck caught in a tight space. The stockers might be up to it, but I don't have any personal experience on when they fail since the only part I've broke on a 7.5 in over 12 years (again - autoxing, hard driving, and drag racing) has been a fragged torsen (worm gear failure leading to catastrophic fubar).

 

is this a fullsize blazer? if so the fronts are kinda iffy. ive got the axle shafts out from anywhere taking a hour to like 5 depending on rusty parts and broken stuff. you have to dissemble hubs and bearings and pull the shafts out.

 

i'm thinking it is a "S" series, with the reference to the ZR there. they all came with the option of 3.73's as well-my 4 door has 'em in there from the factory.

i mentioned that bit of info for you, since it may just be cheaper (and easier) for you to swap the whole front diff.

 

To change out gears in the front diff you first have to drop it out of the vehicle. It is a split case and there is just no way to open it up until you drop it.