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Ultramatic Part Differences
#1
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Pgh Ultramatic
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450352 vs 6480887 High Speed Governor Body
The latter has a pin about 20 thou longer than the former. This keeps the valve farther off the body. When possible, the latter should be used with the 56th style Governor valve to reduce the chance of the valve sticking. The parts are identified by casting number.

450817 vs. 6480640 Rear Pump To Ring Gear Thrust Washer
The former is fiber and 0.064 thick. The latter is steel and 0.048 thick.

470091 vs. 6470250 Rear Housing Assembly
The parts are identified by casting number yet the castings are the same. Instead, the only difference is the spider (the bushing support piece). The 55th type has four holes in pairs. The 56th type has four holes spaced evenly. The part was redesigned for greater strength, but they are interchangeable in practice.

All Seals (not including gaskets)
The 1956 type were improved design over the 1955 type. Irrelevant now.

High Range Clutch, Input Shaft, Converter, Etc.
The 56th input shafts had a finer spline than the ones previous. Anything that is engaged into the input shaft has a different part number for 56 and may be correspondingly identified irrespective of other differences that may exist.

465754 vs. 6480734 Oil Cooler
The 55th type has a seam running down the center of the cooler. The 56th type the seam is on one side, much like a sardine can. The 56th type has better cooling performance. While not necessarily helpful for a 55th, it is recommended to use on a 56th car or 55th Caribbean to dissipate the converter heat more effectively.

470049 vs. G137406 Oil Cooler Line Adapter To Case
The former has a smaller orifice than the latter. The former part itself is obsolete as there is no need to restrict the oil flow to maintain pressure in the converter. It can simply be modified by drilling the hole oversize to match the diameter of the other hole.

440845 vs. 470143 Oil Pan
The 56th type has one less hole than the 55th type. This is most easily identified by the fact that when looking at the pan from the underside, the 55th type will have one reinforcing strip at the front of the pan while the 56th type will have a reinforcing strip both at the front and back edge of the pan. It is important to note that all of the Packard pans have the filler tube fitting at the right of the front side of the pan (looking at the pan right side up). If the fitting is on the front of the right side of the pan, then it is for a Hash car. See Hash vs. Packard Differences. In other words, the drain plug and the filler tube connection are on adjacent sides on a Packard pan, but are on opposite sides for a Hash pan.

458950 vs. 6484046 High Range Clutch Assembly
The 56th type is shorter than the 55th type. If the transmission body endplay is outside the range of selectable spacer washer, exchange one for the other. All which have a "0" stamped opposite the check valve are 56th type, but most are unlabeled. See SB 346. This is not to be confused with the "0" that is stamped into the ring gear as all ring gears are the same.

421073 vs. 6470245 High Range Steel Clutch Disk
The 56th type have more clearance between the disk and the body than the 55th type. Irrelevant.

450552, 450553, 470172, 6484614, 470219 Converter Rear Thrust Washer
See explanation here:packardinfo.com/xoops/html/modules/newbb ... 6809&post_id=288698#forumpost288698

Posted on: Yesterday 19:32
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Email (Parts/service inquiries only, please. Post all questions on the forum.)
service@ultramatic.info
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