The front diff is able to be completely disassembled and rebuilt. The limitation is the choice of gearing for the front axle. As some S-series trucks were offered with 4.10 gearing, you can get that, but I am not sure on the availability of lower gears...

 

Ahh alrighty. Haha..sometimes all this information could be dangerous when ya don't know what youre reading. Thanks for the knowledge sir

 

I've been thinking about putting slightly larger tires on my 99 Blazer 4x4 (Trailbalzer edition), so it was good to find this info. Interestingly, I couldn't find anything in the wheels and tires portion of the forum that addressed the effect that installing larger tires would have on overall performance & drivability. Several years ago I put 30 x 9.5 tires on the stock rims of a Nissan 4 cyl 4x4 5-speed truck and the decrease in performance was really noticable. I'm considering putting the same size tires on my Blazer's stock rims, and was wondering what if any effect it would have on performance. Any thoughts?
Thanks

 

That depends on your stock tire size. If 235/75R15, then you are going from a 29" tall tire to a 30" tall tire which will affectively raise (lower number) your overall axle ratio. The performance hit will depend on what gears are already in there. If you have 3.73 gears you will notice much less of an impact than on 3.42 gears.

 

Even on 3.42s there's not a big difference, but it's definitely noticable. The 4.3L is a lot more torquey than an old Nissan 4 banger

32" tires will be okay with 3.73's... but would be much happier with 4.10s.

The 4.56s would only be if you don't do much highway driving and have larger than 33" tires...

I'm probably keeping my 3.42s for awhile, since I plan on a V8 swap down the road, so I'll have no trouble turning 32" or 33" tires



And Kyle, I think what he meant by "sealed" diff, is that there's no cover to take off...

 

How do I know what gears I have?

3.42 or 3.73?

I have a 2000 4x4 2Dr

 

You're going to have to check the RPO codes in your glove box... There'sa few threads that have the gear RPO codes in them floating around...

 

According to the door jamb, mine came stock with 235 75 15 tires. Guess there's no way of knowing offhand what that means in terms of gear ratio?

 

your in the same boat as me

I gotta snap a pick of my RPO codes so I can tell, and im pretty sure thats the only way to tell.

 

As stated earlier, you have to look at the RPO codes to tell the gear ratio...