Packard Forum Index » Project Blogs

So the 1956 transmission has the same bolt pattern as the '54 Gearstart? I have a Gearstart for my '54 Patrician but it needs a thorough rebuild so if a newer unit will fit, it's all the better. Somewhere I even have the indicator for the different shift pattern.

According to Ross, which I am basing this transplant on, the converter-to-flywheel bolt pattern is the same between the S8's and the V8's. So, if you already have a GearStart, then you can swap the GS bellhousing and the GS oil pan on the 55/56 trans body, and get a 55/56 tranny to bolt up using the 55/56 converter as well.

Obviously, the internal shift characteristics are not tuned for straight eight, so some valving adjustments may be needed.

If your car doesn't already have a GearStart, then youll need more parts as I believe the kick down linkage, actual engine throttle linkage, neutral safety switch, shift quadrant and other parts are unique to the GearStart as opposed to the regular ultras on the straight eight. If you look in the parts manual, you'll see many parts listed for the GearStart that are different.

The GearStart is "basically" a 55 Twin Ultra prototype with an S8 bellhousing, as such, you'll notice that you have to refer to the 55/56 service manual when working on it, as it is not covered in the 51-54 manual.

Aside from swapping the bellhousing, be sure to have the complete trans unit with correct converter for the trans you are using. Input shaft splines are different so 55 and 56 converters will not interchange.

Good point Howard!

Good to know. I have the complete Gearstart assembly including the column linkages, plastic indicator and, of course, the transmission so it seems a better way for me to go, presuming it's even rebuildable. For you, I am anxious to see how it fares with the '56 Twin-Ultramatic.

JMO but if I had a '54 that I wanted to use as a reliable tour car and driver with a year-correct Ultramatic I'd pick the conventional Ultramatic over the Gear-Start in a heartbeat.

For what it's worth, I drove several Ultramatic Packards as every-day cars for years but to compete with modern traffic, I had to manually shift to low range from a stop. Otherwise it was very sluggish although at speed it was fine with so much power you would be pressed into the seat if you hit the pedal hard at highway speeds. I read somewhere that starting in low range isn't recommended but without doing so, even my 212hp 359cid Patrician couldn't keep up! No point in an automatic if you still have to shift for regular driving and the Gearstart seems a way to overcome it, short of installing one of the other make conversions. Of course, to get the most from it you may also need the appropriate ratio rear end.

Don, I drove my '54 Patrician back and forth daily to work for over a decade; surely it's no bolt of lightening off the line in "H" and you have to pick your spots when accelerating onto an expressway or the like, but it certainly wasn't necessary to use low range to do so. But my choice of the regular Ultramatic for touring would be based on durability. Regular Ultramatic behind the in-line 8s could be expected to have a service life about equal to that of the engine, can't say the same for the Gear-Start.

Though I'm generally a purist I find BigKev's plan interesting and will be most interested in hearing how it comes out. By '56 the Twin was about as good as it ever could be, given it's inherent limitations, certainly much improved over the Gear Start or even the 55 Twin.

My hope is that the '56 Ultra, would be very durable behind the S8, as nowhere the amount of HP/Torque as a V8.

That being said, I've run my GS on the converter only for years, and while not a speed demon, I never had a problem getting on a freeway or up to speed.

Did you ever calculate what RPM you're turning at highway speeds running on the converter like that? And the follow up question, what RPM is the upper limit for these engines? I've been wondering how hard I can push my car and not start having parts start swapping holes.