Packard Forum Index » V-8 (1955-56)

Did the '56 Packards with Twin Traction rears have a badge or other indication to easily find out if the car has the option?

I have seen a '58 with a "TT" badge on the trunk, but not familiar with any such designation on the '56 models.

I think it's a very desirable option, yet need to know what I'm looking for to make a positive ID. Perhaps there is something visible on the rear axle, which is always a better indicator than just a build code.

BTW, anyone with a TT who has opinions on how well it works, what it feels like, etc. would be of interest. Is it a "locker" setup or a clutch type system? Anything unique 'n' different?

Anybody have trouble with these?

There was no external trim identification such as was used in 57/58. There may have been a brass tag on the case, some have suggested a "TT" stamping on the case, but over the years many of these tags have been removed for whatever reason. The build slip would of course tell you if the car was so-equipped, I believe the code for it was "PL" for PowerLock. Of course you could also jack up the rear wheels and do the "drive" test.

Based on my own experience and what little I've heard on the subject from others, it wasn't as robust a unit and one might wish for, my own was beat to crap in about 80,000 miles and I replaced it with a conventional carrier.

Diagrams aren't the best but in April 56 service counselor Vol 30 #4 there is a description of twin traction and how it works. Might answer some questions..

"Twin Traction" was the Studebaker trade name for a non-slip differential that I think was similar to the Chrysler products differentials of the same type. I'm trying to find the reference material that I had on these units, but I seem to recall that they might have been provided to both corporations by Wagner. The differential used friction disc clutches. It was available on 1957 and 1958 Packards (actually Studebaker President Classics with Studebaker 289 CID V-8s and superchargers). The option was also available on later Studebakers in virtually all models. A pot metal emblem with the italic letters "TT" in a circle was mounted on the driver's side lower corner of the trunks of so-equipped cars. I had the Twin Traction differential in my 1957 Studebaker President Classic. On Studebakers, a tag was installed indicating that the car had Twin Traction but if it was missing, you could remove the differential filler plug and look for the two-piece case and cross pins used in this type of differential. They were pretty rugged units and I never had any problems with mine. I have the two pages from the Studebaker shop manual for 1957 (when Studebaker first supplied the units) for anyone who might be interested.

The unit was built by Dana and they used two different rearends depending on whether it was Packard or Clipper. The axles are also different between Packard and Clipper. My 400, which was not heavily molested, has a "T" tag attached by one bolt on the rearend cover. It is a single "T" and I am assuming it stands for Twin-Traction.

Thanks for recalling my memory, Randy. You're right, of course, they were Dana units. I couldn't find my reference material. It probably went with the 1957 when I sold it.

After comparing the 56th series Vol. 30, #4, bulletin with the Studebaker shop manual, it looks like the 1956 Packard info was copied word for word in the 1957 Studebaker manual. So Packard introduced the Dana units in 1956 and Studebaker in 1957 for most of their models.

Good info.

Very similar, then, to the "tag" used on other limited slip differentials. I was hoping for something that might be more apt to survive the years, although diff covers aren't removed all that often ordinarily.

THANKS for the specific tag position and stamping, randy!

Perhaps the "infamous" Dana axles have different flanges?

Sometimes axle tubes carry a stamping regarding the build, including final drive ratio. The Chevy axle tube markings I found on my Camaro could be very specific, including the shift that assembled it... I guess they wanted to know who to blame.

Guys,

I'm a new member to PackardInfo.com and am also seeking info on Twin Traction rear ends. I own a 56 400 H/T and it has 2 metal tags. The first is simply the ratio and the second one shows a letter 'T'. I have attempted to attach photo's of both FYI. I haven't jacked up one wheel as yet to see what that tells me but was wondering if anyone can confirm whether the tag with the 'T' indicates Twin Traction? Thanks.

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First, welcome to Packardinfo
I also own a 56 400 and it has the "T" tag on the rear end. It does have twin-traction and I am assuming that is what the "T" stands for. the 13/46 tag says it's the normal 3:54 rear end gear ratio. Post a picture and some info in the Packard Owner Registry. We all like to see pics of members Packards.

Thanks for the welcome. I have now added my car to the registry as you suggested. I also have a 56 Clipper sedan that I'll put on when I get 5 minutes. I have also attached the second photo of the 'T' tag on my car's diff. I tend to think that you are correct that the 'T' indicates Twin Traction. It would be a nice option to have if correct...

Warren Jones

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