Open vs. Locking diff question
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Laughing Gas
Joined: Jun 2016
Posts: 892
Likes: 233
From: Kattarp, Helsingborg, Swe
Open vs. Locking diff question
According to the warranty plate on my '67 it has a 3.50 ratio rear axle, with an open diff. Many years ago (90's) I had a '68 Ranger, and I remember that thing being able to go anywhere, snow, ice, mud, sand, you name it. I have no idea what kind of rear axle it had, but I suspect some form of locking diff (maybe?). My question is, would it be worth trying to replace the rear axle on my '67, or should I just leave as is? If I were to replace it, what should I get? I'm not planning on a bunch of off-roading, but I do want to be able to drive it year round. I live in Sweden, so we get a fair bit of snow and ice...
Lead Driver
Joined: Apr 2011
Posts: 6,399
Likes: 40
From: El Dorado, Arkansas
The first limited slip Ford used was the Equa-Lok differential (1957-1968). This is not a good differential to use for high torque loads.
In 1969, Ford came out with the much improved Traction-Lok torque sensing differential. It is a vast improvement over the older Equa-Lok. However, the 1969 Traction-Lok differential is the worse year of this differential to have, due to (4) large holes in the left half of the differential casting --it's prone to casting breakage in this area.
This problem was revised on the 1970-1986 Ford 9-inch Traction-Lok differentials to do away with these holes.
I replaced the single track 28-spline open differential/C7AW-E 3rd member in my '69 F100 with a 31-spline Traction-Lok differential in an N-case Daytona 9-inch 3rd member and swapped out the 28-spline axles for factory 31-spline axles from a '71 Ford 9-3/8" rear end.
I've never run anything but Ford Traction-Loks but, if I was going to install an aftermarket differential, it would be a Torsen unit.
How a Torsen differential works.
In 1969, Ford came out with the much improved Traction-Lok torque sensing differential. It is a vast improvement over the older Equa-Lok. However, the 1969 Traction-Lok differential is the worse year of this differential to have, due to (4) large holes in the left half of the differential casting --it's prone to casting breakage in this area.
This problem was revised on the 1970-1986 Ford 9-inch Traction-Lok differentials to do away with these holes.
I replaced the single track 28-spline open differential/C7AW-E 3rd member in my '69 F100 with a 31-spline Traction-Lok differential in an N-case Daytona 9-inch 3rd member and swapped out the 28-spline axles for factory 31-spline axles from a '71 Ford 9-3/8" rear end.
I've never run anything but Ford Traction-Loks but, if I was going to install an aftermarket differential, it would be a Torsen unit.
How a Torsen differential works.
Thread Starter
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Laughing Gas
Joined: Jun 2016
Posts: 892
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From: Kattarp, Helsingborg, Swe
Laughing Gas
Joined: Mar 2003
Posts: 789
Likes: 7
From: Durham, NC
Do an Aussie locker, Powertrax or Spartan. Otherwise called a "lunchbox locker". They've been around a while now so they are proven. They are simple as it gets and very easy to install. Absolutely no adjustments needed. Simply pull the shafts. Then the center section. Mark the existing location of the bearing caps and replace at same locations after you install the locker. I usually use zip ties on the caps.
Fleet Mechanic
Joined: Jul 2002
Posts: 1,297
Likes: 34
From: S/W Virginia
I put one of the Powertrax "lunchbox lockers" in a jeep I had. Installed easy, and worked great, but it's a bit clunky if you have a manual transmission. Puts some slack in the differential. And be careful on wet roads, they'll lock when you get on the gas, even in turns 
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Lead Driver
Joined: Jul 2011
Posts: 8,678
Likes: 191
From: On the Edge of the Desert
Originally Posted by gittinwidit
Do an Aussie locker, Powertrax or Spartan. Otherwise called a "lunchbox locker". They've been around a while now so they are proven. They are simple as it gets and very easy to install. Absolutely no adjustments needed. Simply pull the shafts. Then the center section. Mark the existing location of the bearing caps and replace at same locations after you install the locker. I usually use zip ties on the caps.
Originally Posted by idealtrucks
I put one of the Powertrax "lunchbox lockers" in a jeep I had. Installed easy, and worked great, but it's a bit clunky if you have a manual transmission. Puts some slack in the differential. And be careful on wet roads, they'll lock when you get on the gas, even in turns
While they are cheap and easy to install, they are noisy, rough, and increase tire wear noticeably...
They are Great off road! But living and driving on the road everyday with one is a different story.
Plus, being that they LOCK, it can become difficult to turn, even on dry pavement. On ice or snow, I don't think you'd be able to turn much at all.
I really REALLY liked my old traction lock limited slip that I had before this locker. So much so that I have a brand new one sitting on the shelf in my shop waiting to replace this locker when I get the time.
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Cargo Master
Joined: Sep 2007
Posts: 2,468
Likes: 531
From: Chandler, AZ
Any 'limited slip' would be a much, much better choice than 'locker' for snow and ice. You can also get a worn out trac-loc and rebuilt it yourself (new clutches and plates). If you have lots of $$$ a selectable locker like an ARB would give you traction on demand and safety of an open diff on ice. Eaton E-lock and OX aren't made for 9"
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