General rear end questions

[Jthomas]

I'm about to fetch a rear end from a junkyard. My knowledge of all the details about them are pretty limited.

I have an 88 k5

I need an axle to bolt right in place without any modifications. New u bolts I understand. I dont want to have to mount new perches or anything.

I really DON'T know where to even start, there's such a selection. I don't want to go rockwells or anything like that . I was thinking just some stock ass GM 1 tons? Should i go Dana? What size? Does Dana make a FF rear end?
I want something full floating. How exactly can I tell if somthing is SF or FF?
What kinds and what years of trucks have "special" rear ends?

I know this is a REALLY general question

Is there a way to figure out gear ratio?
Is there anything I should be looking for on the axle? Like things to look out for or things to check.

Eventually the axle will be built up, but for now, the truck just has to move on it's own, and I don't want to have another drivshaft made.

Anything is a big help. Thanks

[Jthomas]

Here's my curent set up
Stock 10 bolts. When I bought the truck, I was told they were Dana 44s. I really think thy are GM 10bolts?

They are shimed


And I'll have to remove my shock mount and weld on new rear end



Front of perch.

[J.C.]

Need a pic of the pig

[Jthomas]

The axle from rear of drum to rear of drum is like 57"

[7387chevynut]

yep, those are ten bolts,  

Ten bolt front axles were used by GM in 1/2 & 3/4 tons from 78-91.  

Ten bolt rear axles were used from 82-91 in the solid axle 1/2 ton 4x4's.

Probably be easiest just to replace what you have, 10 bolts arent bad axles, they just dont like super big tires.........lol


if you want a slight upgrade in rear axle strength............then get a 12 bolt rear axle.  GM used it from late 60's till 1981.


For your axle ratio.........pull the rear cover,  jack the axle up and rotate the tires alittle bit, and look on the narrow edge of the ring gear,  thats were your Axle ratio numbers will be found at.   For example.......11/41   is 3.73 ratio.   GM will have a build date stamped in that area as well, something like 3-84, 5-78   that tells you when the ring gear was built

[Jthomas]

Well right now I have 40" tires, lookin to go to 42s. But, I'm running a built engine.

There is nothing wrong with these axles, I just need bigger

[betterbeaters]

get a 14 bolt ff

[Jthomas]

get a 14 bolt ff

Yea i know. How can I tell if it's FF or SF?

And what years will bolt right in?
Which ones had a gov lock?
Which ones had lowest gears? (4.56+)
this is the info I need

[jbexc]

Full float only,don't waste your time with a semi.

[betterbeaters]

your going to have to look to see the gears. gov locks suck. and a ff can have the shafts pulled by leaving the tires on. they have a hub the like 8 bolts that come off the you pull the shaft... google it they have pics

[Jthomas]

I know what they look like.

That's not what I'm getting at. Ill be at a junk yard, how can I tell the difference so I don't get the wrong/right thing

What year truck do I pull the axles from

[Blazin40s]

get a 14 bolt ff

. Literally bolts in place..  and a gm Dana 60 front.  Keep your shims too. 

[Blazin40s]

Check out my project thread.  Big loud.  Will show you all u need to know on my 86 k5

[Blazin40s]

Think there is even the way to tell the ratio with the cover off.

[Blazin40s]

You need em out of a srw 80s Chevy.  Same body as yours.  14ff has a kind of point at the bottom of the diff.  And 14 bolts on cover.  14 sf has a round ish cover on diff.  You don't want that one

[Blazin40s]

Google will help you immensely.  Check out pirate 4x4 they have a d60 front bible AMD 14ff bible.  Will tell u all and has pics. 

[marshall]

axles on a ff bolt in from the outside, if there is bolts in the middle hub of the rim, its a floater.

[J.C.]

A set of axles from a M1008 usually have 4.56s, sometimes with locker front and rear. Dana 60/14bolt FF

[Jthomas]

Do they make a 6 lug 14bolt Ff?

[Mudbuster]

Do they make a 6 lug 14bolt Ff?

only if you wanna spend big money and have hubs costom made. It has been done but not cheap and not really worth it