Packard Forum Index » Modification Discussion

Hi all,
I have been a lurker for awhile but this is my first post. I have a '52 Packard Mayfair that has been modified in a couple of ways, most importantly it has a '56 drivetrain in it (374 from a 400). Actually the whole thing works together fairly well, but the weak link is the Twin Ultramatic. Like a lot of other people, I am getting fed up with not being able to use the car the way I want, mostly because of the transmission. has anyone come up with a really good replacement transmission? I've looked at some of the threads, but it doesn't look like there is a lot of agreement on a solution. What are your thoughts? Thanks in advance.

Properly rebuilt by someone knowledgeable, the Twin Ultramatic should be just fine and not really limiting the driving experience in any way, but then again I'm a purist. Some folks have done the conversion to the Chrysler Torqueflite 727 trans and are happy with it, no doubt you'll hear more from them. This conversion kit is widely advertised in PAC publications and other hobby publications. And I've heard other chit-chat about adopting more modern GM transmissions with an OD feature.

Believe I remember reading of the recent loss of one doing a very promising GM trans project. That one had very decent drive reports but haven't heard if anyone picked it up and has continued with it.

If that one is not available, I think we're back to two known adapters. One from Bendtsen for GM 700R4 trans and one from Sierra Grove for the Chrysler 727. There was a gentleman doing a modified TH400 case rather than a bolt on adapter GM trans. Geared toward Golden Hawks though. Maybe still available but that might require some do it yourself mounting and linkage solutions on a Packard.

Some Chrysler conversions had reported vibration issues although maybe straightened out now. Haven't heard a drive report on the new V8 adapter recently released by Bendtsen. I'd be interested to hear of any new developments as well.

Dear Barry:

Given your car is already modified, keeping the Ultramatic doesn't make much sense. By the time you get through a rebuild and transport costs you have exceeded the Torqeflite conversion.

I would avoid the 4L60 GM because the car is not really up to standards for that level of performance. You don't want to crack up because the car gets away from you.

I never had anybody come to me to fix their twin-ultramatic D range, but it is mostly a valve/timing problem fixed by following the TSB's. I always used High range, but if you want fast acceleration then the 727 Toruqflite is the way to go. Years ago I attended a presentation by George Hamlin and he was very enthusiatic about the conversion. The only negative is I have not seen a PRNDL for the kit.

Barry,


A few years ago when I was looking for a V-8 Packard, I test drove a '55 Four Hundred that had been converted to a manual shift with overdrive. It was an impressively powerful car. I mention this as you my want to consider adapting a stick shift transmission. The problem in doing this will be locating a donor car with which will serve as a parts car. You need a donor car as the parts, bits and pieces necessary to do a correct job are no longer available.

Later, I bought a 55 Super Clipper and had the T-U changed out for a manual shift. The person who did the conversion used a donor car for the parts. I am most pleased with the driveability of the Clipper.

Now, here is another route to take in doing this. You could use the 1954 and earlier Packard-built transmission. These will fit your car and engine, and all the shifting mechanisms from the steering column to the transmission are more available than the '55-'56 parts. Of course you will still need the hard to find steering column shift, flywheel and bell housing.

Something to think about.

(o[]o)

G'day Barry,
Always at PackardInfo, whether a "lurker" or otherwise. But seeing you've now dipped a toe in the water, could I suggest you take the plunge and dive in by including your '52 Mayfair in the Packard Owner's Registry here on PackardInfo?

Thanks to all of you that responded. I'm checking out the conversion kits that have been mentioned. You've given me some things to think about, and now I know that I do have some options. I will put the car in the registry. Thanks again for all your help.

Barry,

Since your car is a '52, a stick shift transmission, clutch pedal and linkages, steering column and shifting levers, and rods and idler levers are easier to obtain for these '51/'54 cars than the same parts for the '55/'56. You would still need to get a manual shift flywheel and bell housing. The clutch is standard stuff. The car will be a good performer with the 3.54:1 rear end ratio.

(o[]o)

Barry,
for including your '52 250 Mayfair Sports Coupe in the Packard Owner's Registry.

I guess the only problem with the stick shift conversion is that Barry's car has a V-8 in it. That creates a real parts problem.

Performancewise, and I will wait for the howls of disent, the Torqueflite will out perform a manual shift even when operated by a professional. So the most codt effective route for Barry is probably the Torqueflite.