#1 Good question man. Not all 8 lug axles were full floaters. A semi float axle was also available, and though the ring gear was smaller, it is still classified as a 14 bolt.
The difference is in the hub. Notice and remember that the 9 inchers that you are familiar with have no hub, they have an axle and flange that suppoerted the weight of the vehicle. You cant remove the axle without taking the wheel off, and the axle itself has the lug nuts attached directly to it.
9 inch axle semi float:


Now look at your D60 rear, and notice the large hub and the 8 small bolts that retain the axle to the hub. easy to identify. Also the drum on a full floater cant be removed like a semi float axle. The hub assembly has to be removed. Unlike the semi float axle where it just slips off. (exception is the ff 10.25)

#2 WMS, is the distance between the mounting surface of the left hub to the mounting surface on the right. You are simply looking for the same width of the wheel mouning surface. Because there are hub differences, you cant use the backing plate, nor can you use the total with at the hubs. These may be different even though the wheel mounting surface is the same. If you want your tires to stay in the samemounting location, this is a very critical measurement. May need a friend to help hold a tape measure.


#3 How to tell if you have a locker or junk carrier? Good question. While I can tell just by looking at so many over the years, explaining over a keyboard can be a little tough. The main reason is because the traction devices fit inside of the big old carrier.
In many cases it requires the removal of the carrier and it might have to be opened up to determine what is in there.
In any case the open two piece carrier is very desireable, and the Detroit simply plops right in the place of the cross and spider gears. Simple as that to install.

Here is a Gov Lok as viewed from the inside when the carrier is opened up:

 

ok thanks.. you have helped me out a ton. i actually know about everything you have told me, it just took more explination to get it to relate to the 14 bolt from what im used to.

im going to hunt some stuff down, ill take mesurements and pictures and get back on here so i can make sure im getting what i need..

again, thanks a lot.

 

Anytime man. You keep building that truck. It is an awesome truck and soon it will be bomb proof! Keep it up. Little by little.

 

since you don't seem to mind answering my questions ill keep on asking them..

theres a salvage yard i stopped at today during work and they said they have a 14 bolt from a 97 2500 thats full floating 8 lug. is this the 10.5" ring?
would this have disk or drum brakes?
is there a web site where i can get a break down of this axle so i know what year trucks have what in them(long shot but worth a try)?

 

Ask away. For suer extreme stuff the debate is open whether or not the later model units were as strong as the earlier ones with the expection of the units with many many ribs cast into the center section.
I believe this axle that you have found will still have drum brakes and will be suitable for you.
Check here to see years and models these axles were found under. These pages help with not only identification for the GM axle, but fords and others as well.
Decent info and seems to be accurate.

AMC Differentials, Chrysler Differentials, Dana Spicer Differentials, Ford Differentials, GM Differentials, Suzuki Differentials, Toyota Differentials,

 

do you think 4.56's would be too numerically low for 39.5's that will be driven on the street mainly? not too much high way but going to events and such.

i wouldn't normally ask but another salvage yard has 4.56 14 bolt now and if it has a locker, it could save me some money i think lol.

 

I like steep gears. you have a 4 speed, so you can get away with the 4.56. man jump on that 14B FF with 4.56 gears. I wanted to save this for a rainy day, but the CUCV trucks that were equiped with detroits all have 4.56 ratios. This axle that you describe has all of the makings for the right axle.
Here is the thing, buy it if it is in one piece and not all tore up. Then once it is in there, drive it. Hit the road in 2wd and see how you like it. believe me, if it has a locker, you will spend most of your time in 2wd anyway. Once you get a chance to drive it, you decide if it is appropriate or not. If the truck digs it, then you are gold, and you pretty much got everything for free. Just have to change the front to match and you are in like Flynn.
This sounds like a great deal waiting to happen, and can save you some big cheddar.

 

Just want to say what a great informative conversation you guys are having .


You're hitting on a ton of great questions I have (and will have in the future).

I'm bookmarking this puppy!!!

 

i was thinking the same thing...im trying to get all the info out of 75f350 that i can.lol

 

Yeah, he seems to be a vat of kick-butt knowledge!!!!!

 

I had 4.56's with 39.5 Super Swampers at one time. To answer your ? No, it was barely enough gear for the street, IMO. But like Ed said give them a shot if there already in there. Maby you will like them..........if you don't have any steep grades around your area..

 

Since we're on the subject anyone know what rear axle is under a 83 F250 4x with a 6.9?

Please say Dana 70!

 

not according to that site that 75f350 linked earlier.

 

According to that link it could be a dana 60, dana 70, Ford 10.5 or a Ford 10.25.

 

Where do you see that it could be a sterling? I looked, and the sterling was not available until 1985. The F250 probably does not have a D70, so your options are getting a little narrow.
Did I provide a bad link???? Maybe I should consider another source.

Have you a pic of the diff? real easy to tell, even with just a pic.