Packard Forum Index » V-8 (1955-56)

Can anybody tell me what type of threads the bell housing retaining screws have (Whitworth or UNC ?!).
Is it imperative to use 55-60 lbs.ft on these bolts?

Tom

Tom,

In the 55 - 56 Parts and Accessories List, available for download from PackardInfo, under Group 3 in the Clutch and Transmission section see Page 36 under 3.510 are listed P/N G179862 All 55th; 56th Screw 7/16"-14 X 1&1/2" - 9 off and P/N 470058 All 55th; 56th Screw 7/16"-14 X 1&11/16" - 1 off. They would be UNC. I think these are what you need but not being a V8 guy I'd wait for confirmation from the V8 guru's.

i used the torque setting that the service manual stated, but if you have a aluminum 56 body on the transmission i wouldn't use that torque value, but if you have a true 55 body it is not aluminum and will handle the torque fine.

I'm laughing mildly, Whitworth threads in a U.S. origin car?

Seriously, somewhere in a box with a couple of hundred bolts removed from Packards, I do have a set of the bell housing to trans bolts, if you can't find something appropriate, let me know and in due course I'll search for them - yours for the shipping cost.

Regarding the torque for the aluminum (1956) case, there was some discussion of that a year or two or three back and my recollection was that there was some very good advice given, though I don't recall it. Perhaps a search will find that old thread - if not, our Ross Miller is the best source of info on the Ultramatics and if he sees this when he next signs on, I'm sure he'll provide guidance based on his very extensive experience. I agree with cli55er that using the same torque as specified for the cast iron case is questionable.

Rocky46 -

I had to check one of your other threads to find out that you are working on a 55 Twin Ultra. The reason this is important is because the 1955 version of the Twin Ultra. had a cast iron case, but the 1956 version used an aluminum case.

The torque specs in the shop manual are correct for the 1955 cast iron case, but they were not updated for 1956. Though there are some good notes about valve body torque, I've never seen any reference on bell housing screw torque for 56th Series in any service newsletter or bulletin, either. However, I've found more than one car where one of those screws pulled through the aluminum case. Anyone working on a Twin Ultra. with aluminum case might want to take a look at this thread:

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?topic_id=5005&forum=3&post_id=53801#forumpost53801

Now, if you have a cast-iron Twin Ultra, then the 55-60 ft. lbs. specs is correct and should be followed. I can't imagine that as a problem for most torque wrenches rated in foot-pounds - a tool that is needed for all sorts of work on these cars. Yet, when working on any U.S.-built automatic transmission, you will also need a torque wrench rated inch-pounds.

BH, you're a whiz at finding old posts. That was indeed the exchange I was trying to recall, and as always even though not always said, thanks for taking the time to dig it out.

Owen -

Well, it's been known to have some hiccups in the past, but this site's internal search function actually deserves most of the credit. I just used the keywords: ultramatic aluminum torque

Though I may have had a leg-up in sifting through the search results, since I recall Randy Berger bringing this up on more than one occasion, I first looked in the thread started by Mr. Pushbutton and aptly titled, Ultramatic fastener torque specs, to which Randy replied.

The search function does indeed work well, as well as the user is at coming up with the best set of keywords. I use it often, perhaps should use it even more and save you a bit of effort on occasion. Anyway, please, take the credit for this and everything else you do around here.

Thanks for your answers.

The reason for my questions is that I (or rather the person who did the job before me) have ruined several threads in the aluminum transmission case, when using torques between 20 to 40 lbs.ft., and of course among others where the self locking screw is to be used.

Another thing is me finding Helicoils 7/16-14 in Scandinavia, I have tried this morning, will seemingly be like finding Whitworth in a U.S. origin car.
Any good suggestions what to do?

Tom

Order them from the US? Postage can't be that much.

Sympathize with your problem, always annoying to find buggered threads.