28 or 31 splines
Thread Starter
|
Elder User
Joined: Apr 2003
Posts: 789
Likes: 0
From: Cheney, Wa
28 or 31 splines
i have a 76 f100 with the 9" rear, i was wondering if there is an easy way to tell if i have 28 or 31 spline axles, and how much would the 28 spline carrier work with a 31 spline mini spool?
Posting Guru
Joined: Aug 2002
Posts: 1,493
Likes: 1
From: Great NW
28 or 31 splines
In order to verify the spline count, you will have to remove the rear brake drum, bearing retainer and axle to check.
My '74 F-100 is a 28-spline. Since you also have an F-100, you too probably have a 28.
But check to make sure...
My '74 F-100 is a 28-spline. Since you also have an F-100, you too probably have a 28.
But check to make sure...
New User
Joined: Apr 2003
Posts: 3
Likes: 0
From: Georgia!!
28 or 31 splines
Whoa! No need to take anything apart! There is an easier way to check which axles you have. There are 10 bolts holding the carrier in the axle housing. One of these bolts will have a small metal tag attached to it. The bottom row of numbers on the tag will give you 2 pieces of information. For example mine says:
3L50 9 S319B
The first number tells me that my "chunk" is equipped with 3.50 gears. Ford used an "L" to replace the decimal point I assume to make it easier to read. The S31 in the last number means it has 31 spline axles. Hope this helps!
P.S. I wouldn't use a spool if you drive on the street, especially if you are running big tires. When you go around a curve the outer wheel is traveling faster than the inner wheel. If the differential can't unlock to allow the wheels to turn at different speeds, one wheel will slip or something will break. Usually the latter.
3L50 9 S319B
The first number tells me that my "chunk" is equipped with 3.50 gears. Ford used an "L" to replace the decimal point I assume to make it easier to read. The S31 in the last number means it has 31 spline axles. Hope this helps!
P.S. I wouldn't use a spool if you drive on the street, especially if you are running big tires. When you go around a curve the outer wheel is traveling faster than the inner wheel. If the differential can't unlock to allow the wheels to turn at different speeds, one wheel will slip or something will break. Usually the latter.
Posting Guru
Joined: Feb 2002
Posts: 2,404
Likes: 3
From: Cleveland, WI USA
28 or 31 splines
Originally posted by jeffh31
P.S. I wouldn't use a spool if you drive on the street, especially if you are running big tires. When you go around a curve the outer wheel is traveling faster than the inner wheel. If the differential can't unlock to allow the wheels to turn at different speeds, one wheel will slip or something will break. Usually the latter.
P.S. I wouldn't use a spool if you drive on the street, especially if you are running big tires. When you go around a curve the outer wheel is traveling faster than the inner wheel. If the differential can't unlock to allow the wheels to turn at different speeds, one wheel will slip or something will break. Usually the latter.
Just out of curosity, do you have or have you ever had a spool or mini-spool in your own truck? I've been running a mini-spool in mine with 33s for over a year and have had no problems. I just put on 36s and am still having no problems.
I'm sure some people have had problems, but there a few others on this site that have been running them for years in their daily driver trucks and had no problems. Not even noticible tire wear.
Again, the beauty of the mini-spool is that it's cheap and easily removed.
Kevin K.
Posting Legend
Joined: Sep 2001
Posts: 30,255
Likes: 37
28 or 31 splines
A solid axle setup is plain dangerous if you live in ice country. Don't run a spool on the street, it is a major nono, just ask any of the diff shops. Use a lim slip etc if you must, but even then it can be a hazard on ice or snowpack. Just because it is "working" doesn't mean it is right or safe.
Trending Topics
New User
Joined: Jan 2008
Posts: 0
Likes: 24
28 or 31 splines
Jeff, I have to dispute that about the S31 meaning 31 spine axle.
That number to the righr of the ratio code has always been Plant code.
It is the Bearing code ie WFE-BK2 that states what bearing is in it and thus will reveal ina Ford book what the axle spline is.
The factory or plant code is a every tag item,whereas, tha spline codse isn't.
See Below.
Ford changed the layout of the tags sometime in the early 70's or late 60's, here is a WFE-BK2 tag, followed by a date code of 4E24 (April 24,1974), the second line now gives besides the ratio-here a 3L50, the ring gear actually used inside-this one is a true 9" gear.This tag is off a 74 Ford truck.
That number to the righr of the ratio code has always been Plant code.
It is the Bearing code ie WFE-BK2 that states what bearing is in it and thus will reveal ina Ford book what the axle spline is.
The factory or plant code is a every tag item,whereas, tha spline codse isn't.
See Below.
Ford changed the layout of the tags sometime in the early 70's or late 60's, here is a WFE-BK2 tag, followed by a date code of 4E24 (April 24,1974), the second line now gives besides the ratio-here a 3L50, the ring gear actually used inside-this one is a true 9" gear.This tag is off a 74 Ford truck.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Senior User
Joined: Jan 2003
Posts: 312
Likes: 1
From: Huntsville, AL
28 or 31 splines
Here is what I think I know about my tag of my '73. Maybe this will help you? Can anybody give me more details?
My tag:
WDM-AC 3GC
3.25 9 331A
WDM-AC- 3:25:1 also the bearing code. What else can this tell me?
3GC- 3=Year ‘73 G=July C=3rd week. Am I close?
3.25- AXLE RATIO 3.25:1 LIMITIED SLIP
9- 9-INCH REAR
331A- assembly plant code. Which plant?
C7AW-E is the case code
Differential Type- C2
My tag:
WDM-AC 3GC
3.25 9 331A
WDM-AC- 3:25:1 also the bearing code. What else can this tell me?
3GC- 3=Year ‘73 G=July C=3rd week. Am I close?
3.25- AXLE RATIO 3.25:1 LIMITIED SLIP
9- 9-INCH REAR
331A- assembly plant code. Which plant?
C7AW-E is the case code
Differential Type- C2
Posting Guru
Joined: Feb 2002
Posts: 2,404
Likes: 3
From: Cleveland, WI USA
28 or 31 splines
Originally posted by Torque1st
A solid axle setup is plain dangerous if you live in ice country. Don't run a spool on the street, it is a major nono, just ask any of the diff shops. Use a lim slip etc if you must, but even then it can be a hazard on ice or snowpack. Just because it is "working" doesn't mean it is right or safe.
A solid axle setup is plain dangerous if you live in ice country. Don't run a spool on the street, it is a major nono, just ask any of the diff shops. Use a lim slip etc if you must, but even then it can be a hazard on ice or snowpack. Just because it is "working" doesn't mean it is right or safe.
True, cornering in snow will be drastically different with a spool than with an open dif.. But if it's slippery, LS or a locker will act like a spool. There won't be enough torque on the wheels to break the clucthes/locker free. Even with an open dif, a rear wheel drive pick-up with no weight in the bed is gonna corner like it has a spool in it anyway.
You're right about "just because it's working...". However, just because you might run into problems several years down the road doesn't make it wrong or unsafe.
I've spent my entire life in Wisconsin and have been driving here for almost 20 years. I've driven virtually every type of vehicle in almost every type of weather. The vehicle you drive is much less of a factor in safety as the way you drive it.
Just my experience.
Kevin K.
Junior User
Joined: Aug 2002
Posts: 57
Likes: 0
28 or 31 splines
I have just put a mini-spool in my 9" with the only difference being that my axles are 28 spline. There is no reason that a 28 spline carrier won't work with a 31 spline spool and axles. The only difference in a 31 and a 28 is that the spider gears are for either a 28 or 31 spline axle. I say go for it and if it breaks, FIX IT. As with any performance modification, everyone you talk to will have an opinion as to wheather it is good or bad.
Certified Thread Hijacker
Joined: Aug 2001
Posts: 14,441
Likes: 59
28 or 31 splines
A 31 spline axle won't even fit into a 28 spline differential. The carrier is the same but you will need to change everything else as well.
Most diff tags are gone on most vehicles, especially now after 25 years of use.
A lot of 31 spline axles will say 31T on the end of the axle.
Josh
Most diff tags are gone on most vehicles, especially now after 25 years of use.
A lot of 31 spline axles will say 31T on the end of the axle.
Josh
Junior User
Joined: Aug 2002
Posts: 57
Likes: 0
28 or 31 splines
I have been worng many times before and will be wrong more times in my life so here goes. When putting in a mini spool you are doing away with all the internals such as spider and bevel gears. So are you saying that a 31 spline axle is so big that it would not fit through the axle tube??? I think that what he wants to do will work just fine. But mabey not.
Banned
Joined: Jan 2003
Posts: 1,457
Likes: 0
From: Grande Prairie, AB
28 or 31 splines
Im contemplating the same thing,
I just cant afford a locker or what have you, so ive decided to get a mini spool for my 9''. I also am not sure whether tis a 28 or 31. I guess i might as well jus take 'er out an look eh?
Padd77 says spool for 31spline will work with 28 aswell, but Bullitt says nay, And my tag is also not there.
Ill giver a whirl.
I just cant afford a locker or what have you, so ive decided to get a mini spool for my 9''. I also am not sure whether tis a 28 or 31. I guess i might as well jus take 'er out an look eh?
Padd77 says spool for 31spline will work with 28 aswell, but Bullitt says nay, And my tag is also not there.
Ill giver a whirl.