Packard Forum Index » V-8 (1955-56)

if you have an aluminum case...are you sure you TU is a 55 then.....are the internals 55 and the case was just swapped to aluminum?

as said 55 case should be iron.

Not uncommon to find a 56 TU in a 55; as Ross said so eloquently a few posts back, many of these cars have been "diddled with" in their lifetimes. Even when they were still relatively new and still under care of the dealerships, the 56 TU was known to be consideraly superior and I wouldn't doubt that some were swapped by dealers (and others) even when the cars were still relatively young.

Thank you all.
Just for the record, I have 1956 Clipper, the torque was 55-60. And I have ordered a helicoil kit from Amazon.uk.
I would appreciate any torque info and experience with reduced
torque settings, as I have had a leak between the bell housing and the transmisson case.

Tom

Rocky, when we rebuilt my 56 Carib tranny, friend Ron commented that the manual torque specs seemed too much given the aluminum case on the 56. We subsequently decided that Packard forgot to update the torque specs for 56 aluminum cases.
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Owen -

Quote:

Well, OK. I just have a habit of chiming in with a pointer when the topic rings a bell with me. Yet, as this site continues to grow in terms of both material and discussion, the search results will get even better.

Believe me, I know how frustrating so-called state-of-the-art web search engines can be; too often, I get either 10 bazillion matches or none at all. After wrestling with that for over a decade, I've gotten a better feel for the right combination and number of keywords, but being able to search within the confines of a site like this is a real plus.

Rocky46 -

Thanks for clarifying this is a 1956 Clipper, which should have a Twin Ultra. with aluminum case.

In the Twin Ultramatic thread that I had checked, earlier, you asked about 55th Series. I assumed too much. If I had looked back further, to your Leaking Twin Ultramatic thread, I would have seen that you had a 1956 Clipper. My apologies.

Meanwhile, my Cosworth Vega has a cast-iron Saginaw 4-speed transmission that bolts up with four (4) 7/16-14 bolts that thread into an aluminum bell housing. The factory shop manual for 1975 advises 52.5 ft. lbs. (reduced from 55 ft. lbs. in the 1974 edition). However, proper torque had as much to due with the amount of material (and threads) as its type, and there's a quite of bit of meat (and thread), IIRC, in the Vega's bell housing.

If you feel that 55-60 ft. lbs. is what caused the threads to strip, I'd follow Randy's recommendation for 35 ft. lbs. of torque.

BAck in the 60's and 70's my brother and I worked on many Ultramatics (or Ultraumatics??) both cast iron and aluminum.
I do not recall any factory notices of any kind recommending lower torques for the bell housing to aluminum case bolts. We never encountered a stripped hole and always torqued to spec.

In most cases Packard was very thorough and with the troublesome Ultramatic if stripping had been common I would think they would have addressed it, for sure those tranny's were disassembled and reassembled more often than most other makes.

Member Rocky says that holes were previously stripped at 20-40 ft lbs. If so, someone was doing something very wrong. Fasteners are to be torqued dry, with no lubricant.
If the threads or under the head of the bolt are lubricated they will go to a much higher clamping force than intended and perhaps will strip the aluminum. Food for thought.

Whenever I get a virgin--which is VERY seldom--I torque those bolts to 50 lb-ft. All those who have been previously loved by some other mechanic get 45. Those who have had multiple lovers who used impact wrenches get helicoils.

Fred's point about lube is very important as it greatly increases the clamping force.

Fred, the problem is not with bolting the alum bell housing to the cast-iron engine. It is bolting the alum bell housing to the alum transmission case. I think 55-60 ft-lbs is an excessive amount. The situation only occurs with the 56 trans as the case in 55 is cast-iron. Refer to page 48 of the twin-ultra section of the shop manual - figure 166.
I apologize for not being more explicit.

Thank you all for your help. Now I'm a wiser man.

Tom