Currie Enterprises rear axle in '68 GMC

[nikwho]

Hello all,
I've recently obtained my '68 GMC C15 that I am building. I have been hard at work. I am about to start my 4 link rear suspension and found a Currie Enterprises 9" with 32 spline Strange Cro-mo axles, Locker, 4:11 gears, 12" dual piston calipers. It is the ratio I was looking to swap to, discs, etc. Basically everything that I wanted. The vest that I could tell, the WMS to WMS is 65 1/8". My understanding is that the '86 C10 10 bolt that currently resides underailleur this truck is 63 1/8" WMS-WMS, but it has 1.25" spacers that allow me to run my 5 on 4.75" Boyd Coddington Junkyard Dog wheels. So, over all, it'd be narrower than current setup. BUT, my hope is to run an off the shelf 12" wide wheel with 315-345 mm wide tires, probably on 18" wheels. I'm trying to see if anyone has a similar enough experience to tell me if my dream $4,000 axle that's available to me for $900 (if I jump NOW) will work for me. I was told that it was under a "late 60's to early 70's" truck previously, but the guy could not provide more info. Any thoughts on a 65" (WMS-WMS) axle under one of these trucks? I'm really hoping that it will work! It even has a parking brake!

Thanks, Nik

[franken]

I'd talk to a local diff shop after really defining the measurements, price point and desires. They might be able to do better than Currie.
Please do make sure to post more stuff in ALL CAPS so we know we're too stupid to understand what you mean in lower case, while you must obviously be a wizard.
Better yet, ask what's the truck worth right now, and realize a new diff adds zero to the resale value...
But its an investment, right?

Bottom line is drums are fine functionally in these trucks, measurements are needed, and you have to decide leaf or not and traditional or not. If you have cubic money, farm out the work and be happy--wait they often F-it up so risk there.

[nikwho]

Didn't realize that I typed so much in caps that I would set somebody off. Thanks for the helpful and constructive reply!

Fraken, are you just high, or are you stupid? Stay out of people's posts with your worthless comments!

I've looked through your posts and I have determined that you are an ignorant troll! Go away!

Nik

[Captainfab]

I don't have the end answer you are looking for but I will clarify a little. The '86 10 bolt should be 63.5" wide. That width plus your 1.25" spacers x 2 = 2.5". That makes your current WMS to WMS 66". What are the width and back spacing of your current wheels? Compare that to the 12" wheels you want and their backspacing to see if it will work with a WMS to WMS that is 1" narrower.

['63GENIII]

I don't have a concrete answer for you either Nik but rather a little advice. It sounds like you have found an axle with just about all of the things you're looking for at a price you can't pass up.

What I did when I found the disc rear axle for my '63 was to make a drawing (if you have your truck accessible to measure) with all of the measurements with your current axle and wheels in place and then (in a different colored pencil) draw in the measurements using the numbers that you have for the new axle and wheels that you're looking at.

For me, it came down to being reasonably sure that the axle that I bought would fit for me to buy it. Also knowing that if once bought and mocked up under my truck, it didn't fit, I could also unload the axle without taking a loss on it.

To me, not knowing much about Currie and the axle that you are looking at, I would pull the trigger if I was;
1. Pretty sure it would fit and..
2. If it didn't fit, I could off it easily without taking a hit on it. From the sounds of it, I gather that you would stand the possibility of making a few extra bucks if you did have to get rid of it. To me it sounds like a win either way.

The only flag that goes up in my mind is why is someone giving you a 4k axle for only 900$. If its a legit quality axle thats in serviceable condition, Id probably jump on it knowing its not gonna be a paperweight.... but then again, if you were to look under my house you would get the impression that I am a collector of paperweights. LOL. Just take your time, do your research as best you can and leave yourself an out if it doesn't fit.

[nonstop]

I've just finished building a few 9 inch centers. Gears and Yukon limited slip alone (without bearings or anything else) were $500-$600 per. As said, if it is legit, and will likely bolt in, even with a few mods, then go for it!

[nikwho]

I have yet to choose what wheels I want to run, so it'll be tough to really determine what will work. But, I really like the idea of making a drawing showing frame width, bed width, current axle width and wheel backspacing plus adding the wider axle width and desired wheel width, which will help me determine the minimum and maximum offset. I can take that and see if some of the 18" x 12" wheels that I like are available in comparable backspacing. I appreciate the helpful comments. I would love to see some combos on trucks that have similar axle widths & wheel combos, but that's getting awfully specific..

Thanks,
Nik

[James the III]

You don't have the wheels yet you will be buying 12" after the fact so the axle width is a moot point..
Remember when you do start measuring for you new wheels and needed offset/backspacing to do so with the brake rotors on the axles.. the thickness of the rotor can be 1/4" measure for the new wheels with the rotors on the axle and axle at ride height, and centered under truck..

[nikwho]

Yes sir! Rotors were on when I pulled the width. I guess that my main concern was that I didn't want to have wheels with a custom offset built. Though, there's not going to be aby wayaround just taking a bunch of measurements and figuring out what kind of offset is going to be required, then figure out if there are many 12" wide wheels available with the offset that I will end up needing. At the end of the day, my question was lazy. Sorry. I was hopeful that someone may have had experience doing what I'm thinking about doing. I'll pull some measurements and gofrom there.

Nik

[nikwho]

Nonstop,
In response to your reply, I figured that for a disc brake swap that also had parking brake provisions, I figured that I would be spending about $600. Plus $200 ish for gears, plus $500ish for a locker. And that $1,300 would still leave me with a $1,300 10 bolt w/ 31 year old brittle axle shafts. Really, even buying this axle for its brakes and 3rd member would make it worth while to buy, then buy a narrower 9" housing with axles, swapping the 3rd member and brakes over, the recouping a good chunk of my money by reselling the Currie housing and 32 spline Strange axles! I'd just need to make sure that I bought 32 spline axles for the new, narrower housing. But, that's still getting ahead of myself. I'm gonna go put the truck up on jack stands and climb under it to take some measurements.

[James the III]

unless things have changed ford 9" are 28/31/33/35/40 spline..
I'm sure it's just a typo..
most times when an axle is this cheap(4k unit for 900 bones.) it's in a circle track housing with camber built into the unit..
but if not, I'd worry about the wheel options later, at 900. bones if it is what it's listed at, you'll have no issue getting out of it for what you paid.. if you have to because you can't get on shelf wheels in your backspace..

[nikwho]

Not a circle track housing. Not even a Ford housing. It's got a Currie serial number tag on it. I've run the build number with Currie Enterprises Tech support and they've confirmed it as what it's advertised to be. I think that the guy just needs to move it quick. It's stored @ his friends house, he's gettig a divorce, moving, that whole bit. So, I'm gonna pull the trigger. Worst case, selling the housing and axles & using the the 3rd member and bakes in a new axle housing would be worth the investment.

James, my phone was auto-correcting 35 to 32 for some reason. It's a 35 spline carrier and axle shafts.

[nikwho]

Found out that he needs the money pretty bad so that he can finish up some job that he has going. He's taking a hit to make quick funds to make good on a promise to a customer. Looks like I'll have my 4.11's, disc brakes and posi much sooner than I anticipated!

Nik

[James the III]

Originally Posted by nikwho

Not a circle track housing. Not even a Ford housing. It's got a Currie serial number tag on it. I've run the build number with Currie Enterprises Tech support and they've confirmed it as what it's advertised to be. I think that the guy just needs to move it quick. It's stored @ his friends house, he's gettig a divorce, moving, that whole bit. So, I'm gonna pull the trigger. Worst case, selling the housing and axles & using the the 3rd member and bakes in a new axle housing would be worth the investment.

James, my phone was auto-correcting 35 to 32 for some reason. It's a 35 spline carrier and axle shafts.

Never said it was a oem ford housing, just ford 9" based.. it's either that or a dana 60..
my bet a fab'd 9"

[nikwho]

Originally Posted by James the III

Never said it was a oem ford housing, just ford 9" based.. it's either that or a dana 60..
my bet a fab'd 9"

Yes sir! We were on the same page, I was just trying to provide a bit more info. It is a Currie 9" housing with 35 spline axles, nodular iron 3rd member,

[nikwho]

I'm gonna go pull this thing apart to make sure that there isn't confusion about axle splines. I'm hearing 35 splines and wondering if he's not citing the yoke splines, instead of axle splines. Either way, I'm in. Will be a solid axle either way.

In casee someone else finds this in a search, I'll post my findings from pulling a bunch of measurements. They all made sense to me when I was measuring and typing into my phone. If anything isn't clear, I'll try to clarify. This is just what I'm finding on my 1968 GMC leaf sprung (for now). Part of my wanting to get an axle now is wanting to fab my triangulated 3-link/4-link once, woth the housing that will stay in the truck. I'm thinking that I'll probably end up buying a new fabricated 56" 9" housing and cro-mo axles and fab my 4 link with that. Though I haven't landed on wheels as of yet, I don't want a goofy look to the truck. I'm thinking that this 60" housing (65 1/8" WMS-WMS) is going to be too wide for my purposes, regardless of whether I could make it work or not.

Here's the entirety of my measurements that I took of the truck:

Currie 9" - 65 1/8" (WMS-WMS)
60" backing plate to backing plate.*
Approx 48 1/2" c to c axle pads

Current 10 bolt in truck:
63 3/4" WMS-WMS
With spacers (1" per side, not 1.25" as stated above) = 65 3/4"

Truck measurements:
75" outside to outside (79" outer most surface of bed sides, accounting for wheel being 2" inside of outter most surface of bed sides)

Inside of wheel tubs 14.5" in from outer most surface of bed side.* = 12.5" to edge of safe measurement for wheels.

I measured this way because I was using a shortened drywall square off of shop floor.

Distance from wheel tub to wheel tub:
79" - (14.5" - 14.5" = 29")* = 50
-2" per side to get to inside wheel mount limit = 75" - 12.5" - 12.5" = 50"

Tubbed to 41" w/4 link
Tubbed to 44" leaf springs

From center of truck:
(All measurements are from axle center)
Stock:
25" inside of stock tub
+ 12.5" of wheel room
Total tire/wheel area = 25" to 37.5"

Tubbed to leaf sprigs:
22" inside of tubbed to leafs
+15.5" of wheel room
Total wheel/tire space = 22" to 37.5"

Tubbed to where 4-link bars will be:
20.5" inside of tubs
+ 17" of wheel room
Total wheel/tire space = 20.5" to 37.5"

Axle:
Current 10 bolt (1986 C-10)
63.75" ÷2= 31.875" (31 7/8")

with spacers:
65.75" ÷2= 32.875" (32 7/8")

Currie 9":
65 1/8" ÷2= 32.5625" (32 9/16")


So, tubbed to 4-link w/ 9":

Axle would fall 32.5625" into the 20.5" to 37.5" max wheel opening.* So, outside of wheel could be 5" from WMS (37.5-32.56" = roughly 5")
12" wheel will require 7" or less backspacing (2" offset)
This is a 60" housing (flange to flange)

A 58" housing (63 1/8" WMS-WMS):
31.5625" C to WMS would require 6" or less backspacing (zero offset/WMS centered)

A 56" housing (61 1/8" WMS-WMS)
30.5625" axle center to WMS would require 12" wheel to have 5" or less backspacing

[68c10airstream]

Nikwho, I purchased a currie new replacement for my c10 and dealt with a lot of fine steel shot inside in nooks and crannies. Ended up pressure washing the insides, passing a magnet around and rinsing the heck out of it. I also dealt with a fair share of rust film inside the housing, had to remove it with metal prep. Total shot removed was at least a spoonful. Between the face of the diff mounting studs wearing through the shipping box and getting beat up and had to chase threads, etc, just take a few minutes and check the inside for debris. Good luck on the nicely priced diff!!

[nikwho]

Wow. That's interesting! I wilL pay close attention to that. So, I've aquired the axle. Actually just traded a SBC long block for it. I jumped because, even if I buy a new housing and axle shafts, I'm Way ahead with the Yukon posi, 4.11 gear set and disc brakes. Plus, I can sell this Currie housing and Strange axle shafts, if need be, to offset the price of buying the narrower setup.

I've narrowed a 9" before, that required pulling the tubes from the housing, shortening, then heating housing, pressing tubes back into it, welding it up, then truing with a jig that I built, along with some careful heating and quenching to pull the tubes straight. Turned out pretty good, but I told myself at the time that I wouldn't go through that again; that I'd just buy a housing that was the correct width. Anyhow, before I get too ahead of myself, when the time comes to buy new wheels, I'll worry about the hehe housing width. In the mean time, I've decided that the he hehe 10" wide Boyd wheels that I'm currently running will indeed fit with the 65" width 9".

As CaptainFab pointed out, the current axle is 63.5" wide. I made a mistake on my spacer width. They are actually 1" wide, so my current width should be 65.5". I measured it at 65.75", but was getting creative with some straight edges and a carpenter square to measure. So, I've got space now, plus this new 9" is 0.5-0.75" narrower than my existing setup. I'm sure excited! I do axleppreciate the help that you guys contributed while I worked my way through this, evendors though I got a little lazy by asking, instead of getting my butt out on a creeper and pulling some numbers.

Thanks much!
Nik