I have a completely stock 4 dr. ls 4x4 with 81K miles and i am looking to upgrade the rear end. I hate it when I get on it and I am peg legging it (right rear spins) and also, i heard that different gearing greatly enhances freeway driving, and may have a (slight)positive impact on gas mileage since right now at 65 sometimes the tranny can't decide between 3rd and 4th gear... anyw help or advice would be appreciated.

I found this rear end on ebay and it says it is "an easy bolt in upgrade for all 82-04 blazers" this doesn't seem like it would be an easy bolt in direct replacement, but someone let me know if this would be a good route to follow.

 

Gearing advice doesn't help us much until we know what your rig has...

As for the rear end "upgrade" going to the same sized diff isn't really an upgrade... You can pick up the gov-loc G80 on it's own for less money.

And year of vehicle helps...

That axle IS a direct bolt in, because it's only difference from what you probably have is disc brakes in the rear, aside from the locker of course.

 

mentioned the year in the topic, it's a 99 but no biggie. anyways, My uncle told me I have the higher gearing for my year and that the 3.42 is better. If it's not worth the money and I can still install a g80 on my rig, then I will go that route, at least that will get my left rear involved in the driving. I am pretty sure I have 4 wheel discs too.

 

Sorry, forgot that, lol.

The "higher" gearing? there's more than two options for these things...

3.08, 3.42, 3.73, 4.10

3.42's will probably get you the best city/highway mileage combo with stock tires.

 

Take a look at the RPO list in your glove box. You're looking for a GTx code where 'x' is a number. You can decode the whole list if you'd like (search 'Regular Production Option').

Anyway, since you are a 4wd, for a gear ratio change, you would need to change the gears in the front & rear diffs ($$$). If your truck is hunting for the proper gear all the time, I'm thinking you already have the 3.42 gears. 3.73's would make for less hunting as it would have a higher mechanical advantage.

You can find lockers that will fit into the open diff case that you have. Lockers are not the best for on road use however. I am unsure of the availability of a drop in LSD (limited slip diff) that could be assembled into the stock diff case... I believe you can purchase an LSD diff for the 7-5/8" diffs as these were used in the f-body cars as well and have a pretty good aftermarket.

Hope this helps!

 

Yeah, you can get some pretty nice LSD's in there... But I wouldn't reccomend a locker, unless it's a gov-loc, or controllable one, unless you off-road.

 

is the g80 a difficult install for someone with the right tools and a moderate mechanical inclination? Also, does it make a big difference in daily driving, mpg, or anything small like that? I wouldn't care much because it seems the benefits heavily outweigh any drawbacks that i know of.

is there any similar diffs for the front or is it necessary.

 

If you don't mind a little ratcheting noise, Lock-Rite will work great for ya.

You shouldn't have any change in MPG...

The G80 is only useful if you don't do any hardcore off-roading... Good for a little help getting going on snow, basically, lol.

Unless you have the iron front diff, I wouldn't reccomend doing any kind of locking on the front end.

 

I guess my intentions for the vehicle may help with more advice. I do plan on mild offroading on occasion, nothing serious, mostly gravel roads with the occasional mudholes in the way. Also I am near Seattle and I do go places with decent amounts of snow in the winter so that would be the other time I would use 4 wheel drive.

 

Then the G80, if you can find one for a good price would be good for you...

I haven't really had any problems with mine so far... Haven't gotten stuck yet, lol.

I plan on upgrading as soon as I can afford it...

Too bad I can't sell ya mine.