Packard Forum Index » V-8 (1955-56)

Ross, I think mine is still all original. I purchased my 400 in 1972 and the rearend is original to the car. The previous owner is a friend of mine who purchased car from original owner. When I have rearend jacked up and turn one wheel, the other wheel turns in same way. I always thought this was a way to tell if TT or not.

I need to do some asking around but the Twin Traction carriers should be a standard Dana/Spicer Power loc.
It is still a highly regarded unit, GM basically copied it for the fabled 55-64 Olds/Pontiac rear ends.
The only major change is more axle splines, the more, the better. (to a point)
Guessing that Craig would be an expert on these??

What is the 56 senior rear axle, a Dana 53? I only have one experience with them and that's on my 56 Carib that had the TT. When I bought it at about 78,000 miles from the original owner who gave the car overall impeccable maintenance, the TT components of the carrier were very severely worn, pinion bearings shot, and as a result the ring and pinion useless. I replaced it with an NOS non-TT carrier and new ring and pinion sourced as I remember from Patrician Industries.

The TT part of the system aside, I'd much rather work on a Packard-made rear, far easier to service (no need for a case spreader, etc.). My experience limited as it is says the TT is not particularly robust. Both of my rear axles had the white (or yellowish) daub of paint on the ends indicating that they were the final generation of the axle upgrades. I don't hear anyone talking of axle breakage so I'd guess all the defective axles are long since out of circulation.

EDIT: I rather doubt lubrication was involved in the wear of my TT, there was a partial case of this stuff in the trunk when I bought the car. Unfortunately I was retired at the time and never had a chance to have this stuff analyzed to see what it contained.

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64Avanti Quote:

Certainly not. I have some familiarity with rear ends in general and a little with the Dana 45/53 used in Packards as well as the 57-64 Pontiac big car rear ends. Owen_Dyneto's relating about the TT being a problem is news to me. Of the two 56 400 parts cars I have, neither has TT.

I can tell you that the C-clip Chevy style rear end used in millions of vehicles is a P.O.S. The engineer(s) who designed that should be shot.

Almost all resto-mods on the road or planned today use the Ford 9IN rear end.

Craig

Never had a problem with the axle shafts in any of the three running 56s that I have. Seems to me, from the available factory evidence, that Packard was pretty aggressive about weeding out the early shafts that failed (Dana/Spicer's fault, not theirs). Of those three cars, only my Carib has Twin-Traction, but I've never tested it, let alone opened up the case to inspect it.

My dad had no troubles with either the shafts or the TT diff in his 56 Exec over the nearly 75,000 miles he put on the car, which he purchased brand-new. I'm reluctant to add that one evening at the local watering hole after work (and a few beverages), he even threw a chain around the snout of the axle housing and towed a dump truck far enough for the driver to dump the clutch to get it started.

Meanwhile, the term Power-Lock is merely a trademarked name applied by the supplier to a variety of limited-slip differential designs used over decades - marketing hype. The name has nothing to do with quality or durability.

When the TT gives up the ghost, you're pretty much SOL if you have any hopes of retaining that feature. IIRC, there are three versions of the TT diff between 1956 and 1958. While cases are interchangeable between 57/58 axle housing, I don't think so for 56 - at least not with Senior cars. New parts specific to that particular edition haven't been available from the supplier in years. I know of a Carib across the line in OH was restored over 20 years ago; the owner told me that only help the supplier offered was to replace TT diff with a standard one. I suspect that NOS parts are practically unobtainable, and I wouldn't wanna play Russian Roulette with a used one. Yet, I have heard of some owners having the cross-pins welded to the diff case to get by.

I never heard of any major problems with the 55 and earlier axles built by Packard. I only ever owned one 55 (some 20 years ago), and I never got around to restoring it. It had just over 58K on the clock when I bought it, but looked more like 158K.

However, I see no real benefit of swapping a 55 axle assembly for a 56 unit WRT to the purposes for which these cars were intended. Mind you, I have no interest in rodding or racing these cars. I can put the time and money to better use on other aspects of the car.

When I bought my '55 Patrician someone had already installed a '56 (Aluminium Case) Twin Ultramatic and Twin Traction rear end under it. So far both are working great (or were when I started my rust removal and repaint project about a year ago).

I checked it out in low gear in the parking lot of the tire store when I bought my last set of tires. Laid two perfectly matching strips of rubber for about 250 feet.

The store manager (who didn't believe it had Twin Traction) was impressed.