So I was going down town the other day and I hear a huge crack from the back of my truck. Only to find out my rear differential blew up. Gears came loose and shot out the cover. It's an '86 Chevy K5 Blazer. It is stock. I need advice on what I should put on instead? Should I just put on a GM 14 bolt or will a Detroit Locker do fine? Need advice.

 

Spider gears, or ring and pinion let go? The 8.5" axle should handle the power/weight. A 14 bolt is almost always an 8 lug, but there are a few 6 lug ones out there(metric semi floating) if it's just the spiders that let go, a lockrite would be a simple fix if the carrier isn't damaged

 

find out what gears your tranny running, and go from there, if you dont beat it, nothing to worry about

 

unless youre running big tires or insane horse power can probably just pick up another stock rear end.

 

A 14 bolt full floating axle is a great upgrade. They are easy to work on, relatively cheap and available. You should not ever worry about breaking a 14b unless you're a maniac on the throttle...

Pros:
Strength
Initial cost
Direct bolt in
Cheap disc brake conversions
Full floating axle shafts (shaft only applies power, does not support weight of vehicle)
Stock ratios commonly 4.10 or 4.56


Cons:
Weight
Size (if running less than 35" tires pumpkin will become anchor)
8 lug front end need
New rims necessary


My opinion would be to upgrade now instead of dropping any money into a 10blt, but I'm just one man.

 

Really going to try and find a 14 bolt. Has anyone put in a Detroit True Trac in a 10 bolt? And putting in a 14 bolt from a 10 bolt, is their any modification needed?

 

Also, why is it necessary to switch to the 8 lug? Is it only for Aesthetics? Stronger I'm sure. Also, I know GM stamp the diff gear ratio and limited slip or not onto the diff. Where on it could I find this info?

 

if you get one out of a 3/4 truck it will basically bolt right in. the ubolts and ubolt plates are different so make sure you get those too with the new axle if you go this route. other then when i did mine the brake lines are the same and the driveshaft worked also.

the 14bolt only came as a 8 lug axle thats the problem so youre going to have 8 lugs in the back and 6 in the front. makes carrying a spare tire kinda difficult. they do make a semi floating 14 bolt which is a bit weaker which i believe is still a 6 lug.

the ring gears have the numbers stamped on them that tell you what ratio it is so you have to take the cover off. reading the tag on a old axle is never a good idea cause you dont know what the previous owner did to the axle.

 

You said in your first post that the Blazer is all stock. Why not just put another 10 bolt in? They're cheap, plentiful and easy to replace.

 

I agree unless you plan on going wild shortly. I have a set of k5 axles under our rustbucket mud buggy (came with them). Even with 36s and us ******* the crap out of it in the woods every winter for the last 12 years they have held up fine.