Limited slip diff.
 

When did Ford first offer limited slip differential ???
Or,whatever Ford called it ???

Re: Limited slip diff.
 

No idea, but my 67 mustang with a 9in had a limited slip (not sure for the correct term).

Re: Limited slip diff.
 

Also the 8 inch rear had limited slip. I think a slang term for them was a POSI. I'm looking for one but most are quite expensive.

Re: Limited slip diff.
 

1965 Shelby GT-350s had Detroit Lockers. It was an option on the '66 GT-350s. The guy that bought my '66 GT-350 was too cheap to pay for one. I don't know about the Fords? Maybe some of the earlier 4x4 pickups had them?

Re: Limited slip diff.
 

"Posi-traction" was the term used by General Motors; it may have been copyrighted, not sure. Dana Spicer may have been he first to build a limited slip, and Studebaker among the first to offer it.

Re: Limited slip diff.
 

This is what I can find online. 9 inch Ford axles date from around 1957. Ford used two types of locking traction systems, the early system being called Equa-Locks and the later units were referred to as Traction Locks. I couldn’t find any specific first date for the use of the Equa-Locks, but there are examples in 64. They were used maybe as late as 69. Some later 67 vehicles seem to have used the Traction Locks. Traction Locks were used after this time period.

Ok, Edsels started using the Equa-Lock in 1958, Ford Passenger Cars in 1959 & Mercurys in 1958.

Re: Limited slip diff.
 

Good info from J. If still in doubt, I'm sure Vinny's girlfriend could tell us

Re: Limited slip diff.
 

Most of the more popular rear axles can be fitted with a limited slip differential set up but they do tend to have a limited life time as well. The clutch packs wear out and have to be replaced. There are some set ups that last longer than others but they likely cost more too.

Re: Limited slip diff.
 

I believe it was " Traction Lok " .

Re: Limited slip diff.
 

Just weld up the spiders........what could possibly go wrooooooong ?
Charlie ny

Re: Limited slip diff.
 

"weld up the spiders"
*********************************
Isn't that what they did in the days before limited slip
to get better/more even traction ???

Re: Limited slip diff.
 

Good info from J. If still in doubt, I'm sure Vinny's girlfriend could tell us


Is that your cousin Vinny? :)

Re: Limited slip diff.
 

1957 was the introduction of the 9-inch. The next year they debuted the carrier that took plates...... the limited slip setup.
I have ‘58 guts inside a ‘69 pig in my ‘68 Mustang.

Re: Limited slip diff.
 

Man are they hard to move around on pavement by hand! Especially with rear tire stagger!!

Re: Limited slip diff.
 

I believe that it was 1959.

Re: Limited slip diff.
 

Did you see the manual page I posted in #6? It list the years, Ford was 59, but Edsel & Mercury was 58.

Re: Limited slip diff.
 

Can't speak for Ford but I know my 59 IHC pickup has a locking differential with the tag on the dash indicating "Power-lock differential) It took a special fluid for refill too. I think I still have a can of it here. A Chryco product. I found the power lock differential to be a little "squirrely" on muddy roads. It would spin both wheels and that tended to push the truck in directions I might have been intending to go. I recall one episode of sliding off the muddy road and shearing the top off a big anthill before spinning back onto the road and resuming my journey.

Re: Limited slip diff.
 

My 62 Continental convertible has it.