1968 GT350 Axle Spline count

[gt350shelb]

fyi  my car has 3.89  and spec case but it is nov build


http://www.kevinstang.com/Ninecase.htm

[gt350hr]

   Paul Bartus , as quoted on Kevin's site page is wrong about the "magnesium" being added to grey iron to make it "nodular. The material added was/is manganese. Big difference.
    Also ALL 9" equalocks were 28 spline . Never 31 that was a traction lock only. Pre '68 31 spline "locking axle" cars were Detroit lockers.
   Randy

[Bob Gaines]

   Paul Bartus , as quoted on Kevin's site page is wrong about the "magnesium" being added to grey iron to make it "nodular. The material added was/is manganese. Big difference.
    Also ALL 9" equalocks were 28 spline . Never 31 that was a traction lock only. Pre '68 31 spline "locking axle" cars were Detroit lockers.
   Randy

Randy's page is more accurate then Kevin's page  .

[Corey Bowcutt]

I did get a chance to Check out my axles and gear ratios this past weekend and I do in fact have 31 spline axles noted by the 3 counter bored holes in the end of the axle.  I also rotated my drive shaft and counted the # of turns for 1 rotation of the tire and it is in fact a 3.50:1 ratio.  I also noticed that I appear to have posi traction.  I say this because when rotating the drive shaft both tires rotate in the same direction.  Also when I rotated one tire the other rotated as well in the same direction.  Does this indicate posi traction?  If so did they come with posi traction?

[gt350hr]

   Corey ,
      Ford called it "Traction Loc" and it was an option.  If your tag says 3L89 , then you r diff was originally equipped with one. It would also show on the Marti report. If not , they are often added to improve traction. It is also interesting that  GT350s  got 3.89 gears not 3.91s  which were "new for '68".
     Randy

[shelbydoug]

There was also something about a three disc and a five disc limited slip.

I don't remember the details but it might have been equal-lok vs. traction-lok?

[gt350hr]

   Doug ,
     That applied to Equalocks only which as I said were all 28 spline. The clutches were not "torque sensitive" like the later traction locks are. initially they had four steels and three frictions with 2 "Bellville" springs ( conical ) for clutch pressure. later units had 5 steels and four frictions with one Bellville spring. Traction locks have 4-1/2 "friction discs" and steel plates as one steel plate has friction material on one side. The traction lock design uses the "wedge action" of the spider gears to increase the load placed on the clutch pack , hence the name.

[shelbydoug]

   Doug ,
     That applied to Equalocks only which as I said were all 28 spline. The clutches were not "torque sensitive" like the later traction locks are. initially they had four steels and three frictions with 2 "Bellville" springs ( conical ) for clutch pressure. later units had 5 steels and four frictions with one Bellville spring. Traction locks have 4-1/2 "friction discs" and steel plates as one steel plate has friction material on one side. The traction lock design uses the "wedge action" of the spider gears to increase the load placed on the clutch pack , hence the name.

Aren't those clutch plates sourced from the C4 automatic transmissions as well?

I bought my first one over the counter in 1972 from my Ford Parts guy.

I had taken in an 9"-3.50 with an Equal lock, a "N" housing and 31 spline axles from, a 69 casting date, from of all people, a Ford Factory rep. I think he's the guy that wanted the 4.44 Detroit locker? I think I made about $150 on the deal?

That Equa lok started some discussion, not necessarily an argument. I remember the issue was it was 3 disc's. Maybe it was 28 splines? Huh?

I was a 23 year old Architect and I'm not supposed to be getting greasy crawling around under these things so it wasn't a matter of what is supposed to exist, it was a matter of what was in front of me.

The Equa-lok got sold off for $50 just by itself. No one really wanted it. The Traction-lok's are nice units. Nice and quiet.

Not like the Detroit lockers. Gee-se. That one almost got me arrested and I was only going 10 miles an hour IF EVEN THAT!

[gt350hr]

 No traction lock clutches are all by themselves despite being close in size to a C4.

[TXShelbyman]

Not like the Detroit lockers. Gee-se. That one almost got me arrested and I was only going 10 miles an hour IF EVEN THAT!

Now you're scaring me Doug. My car originally had a 3.00. Someone changed it to a 3.50 with a Detroit Locker. Tim sent me some info stating that my car had been in for warranty work on 7/6/68. Rear end rebuild including a new ring an pinion. I'm wondering if that is when they changed the gear out. Not to derail the thread, but does anyone know why the build sheet shows two digits for the axle? My build sheet shows 76 but the axle code on the door tag is 6.

[jguyer]

I did get a chance to Check out my axles and gear ratios this past weekend and I do in fact have 31 spline axles noted by the 3 counter bored holes in the end of the axle.  I also rotated my drive shaft and counted the # of turns for 1 rotation of the tire and it is in fact a 3.50:1 ratio.  I also noticed that I appear to have posi traction.  I say this because when rotating the drive shaft both tires rotate in the same direction.  Also when I rotated one tire the other rotated as well in the same direction.  Does this indicate posi traction?  If so did they come with posi traction?

Do the 3 counter bored holes always mean it's 31 spline axle? Had a 77 Granada with axle of that type.

[shelbydoug]

Not like the Detroit lockers. Gee-se. That one almost got me arrested and I was only going 10 miles an hour IF EVEN THAT!

Now you're scaring me Doug. My car originally had a 3.00. Someone changed it to a 3.50 with a Detroit Locker. Tim sent me some info stating that my car had been in for warranty work on 7/6/68. Rear end rebuild including a new ring an pinion. I'm wondering if that is when they changed the gear out. Not to derail the thread, but does anyone know why the build sheet shows two digits for the axle? My build sheet shows 76 but the axle code on the door tag is 6.

The problem with the "law" with MY Detroit Locker was that on a left hand turn, it would lock the inside tire.
There was just a simple situation where there was a traffic light that crapped out and we had two "motorcycle" cops directing traffic.

At my turn at the light, the cop signaled to me to turn left. The car was idling at 800, I let the clutch out easy, just feathered the throttle as one normally would, and here goes the locker. It locks the tires and as I turn spins the tires and leaves rubber.

OK, I'm not going to call anyone names. Let's just project a scenario where I need to explain to the "motorcycle contingent in 'Dirty Harry'", exactly WTF "my problem is"? Not a comfortable scenario.

The Traction-lok was in the car by the next weekend.

[gt350hr]

I did get a chance to Check out my axles and gear ratios this past weekend and I do in fact have 31 spline axles noted by the 3 counter bored holes in the end of the axle.  I also rotated my drive shaft and counted the # of turns for 1 rotation of the tire and it is in fact a 3.50:1 ratio.  I also noticed that I appear to have posi traction.  I say this because when rotating the drive shaft both tires rotate in the same direction.  Also when I rotated one tire the other rotated as well in the same direction.  Does this indicate posi traction?  If so did they come with posi traction?

Do the 3 counter bored holes always mean it's 31 spline axle? Had a 77 Granada with axle of that type.

    The three holes are there for machining operations. The "center" is a lathe center and the outer two are holes for a "driver" for the spline operation and some turning. While this "precision method" was used for 31 spline axles , it is not unique to them. '60s axles had the three holes and were 28 spline. ALL 31 spline "performance axles" did have the three holes through '73. The process was also used on 28 spline axles from '72 forward on some vehicles.

[jguyer]

gt350hr, thank you for the explanation.