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Can someone tell me why my '56 400 pushbutton twin ultramatic has a tendency NOT to shift out of 1st gear when I'm in "Drive"? It shifts fine when I'm in "High"?

It sounds like a sticking valve in the valve body. When was the last time you changed fluid? If you have a torque wrench that will read the small torque settings on the valve body bolts, then drop the valve body down, disassemble it and clean all the bores with a long brass bristle brush (I use gun cleaning brushes), measure all the springs comparing them with the values in the shop manual. Assemble it carefully and bolt it back up using the torque specs in the manual - DO NOT OVERRTIGHTEN. Starting in Drive right is different than starting in drive left. Study the pressure charts - it may provide a clue where to look closely.

Though Hotrod has a '56, you bring up an important point, Randy.

Having started out my life with a pushbutton shift on a '56 Exec, I found the Drive-Left/Drive-Right thing very confusing with the (PN^D^LR) indicator lens of the 55th Series cars. (I only ever owned one '55, never drove it much, and sold it 15 years ago.) Yet, the function of those positions becomes more clear when you compare them to the revised (PNHDLR) indicator lens of a 56th Series car that's equipped with a manual selector - even though that order seems a bit dyslexic compare to other BrandX cars I've owned.

Drive-right starts out in Low, then shifts, automatically, to High (like "D" on 56th Series). Drive-left starts out in High, bypassing Low altogether (like "H" on 56th Series).

Do I have it right?

Regardless of that, proper torque of the valve body screws was a hot topic in factory bulletins.

Let me just add that a steady diet of "D" driving is a bit harder on the transmission internals than a steady diet of "H" driving, especially if you've got a heavy foot.

It would be helpful to have a bit more information. When you say a "tendency not to shift" does that mean it never leaves first or will it eventually shift and if so, will it go all the way to direct drive? Does it consistently fail or just occasionally. If eventually something happens, then a couple of possibilities besides the sticking valve also come to mind but would still need more information. At any rate, I'd go with Randy's suggestion and at least do the fluid change and see if anything changes before going further.

Thanks for all the good info. I should be able to get to this puppy in a couple of months.

It consistently does NOT shift when I'm in the "D" position regardless of my speed. I've even tried de-celerating to get it to change out of 1st gear, but it still does not change. However, once in a blue moon, it surprises me and decides to shift when I least expect it to. When it does shift, its at around 10-15 mph and I'm not accelerating hard.

Since I'm guilty of having a heavy foot, am I correct in understanding that I should use the "H" position more so than the "D" position? Under what situations would I use the "D" position?

Before I tear into the tranny, are there any additives or fluids I could use to unstick any sticky valves if that is the problem? Also, would my using Dextron II have anything to do with it not shifting out of 1st gear?


My '56 Senior pushbuttons are on the right side of the column, is this what you mean by "Drive-right or Drive-left"?

Ok, what you're experiencing is similar to my experience with my '56 Pat. What I did was change the fluid (using Type F), drive it about 500 miles, change the fluid again, drive it 500 more miles, change it again and drop the pan to clean out all the crap, clean the filter, then fill it back up with B&M Trick Shift, along with an additive that's only available at Ford dealerships, and may not be available anymore. It's a friction modifier used in the newer Ford vehicles that require Mercon V fluid. When they first come out with Mercon V, it didn't have this additive in it, so they had to sell it separately. Like I said, it may or may not still be available, as it was for a recall, but it sure as heck fixed pretty much all the shifting problems I had. I was working at said Ford dealership at the time, and had access to this more easily than the normal guy. If I had the foresight, I could have bought 5 or 6 more bottles, but I never did. Maybe this will help you.

Re: Drive-left, Drive-right
When first introduced in 1954 and carried over into 55-56, the selector quadrant for the automatic showed a DRIVE-left, and a Drive-right position. Drive-left corresponds to "H" on your pushbutton selector and Drive-right equates to "D". The selector quadrant was located where your "BRAKE" light is now.
The quadrant had an arrow/pointer to the left of a "D" and also to the right. The owners manual referred to Drive left and Drive right. You have to keep that in mind when reading discussions on this subject as many people have a 54 or 55 and are used to this reference.

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someone asked: "Can someone tell me why my '56 400 pushbutton twin ultramatic has a tendency NOT to shift out of 1st gear when I'm in "Drive"? It shifts fine when I'm in "High"?"

Does this happen all the time or ONLY directly after pushing the D button???

My 56 Exec does the same thing once in a while. Especialy going from P to D or R to D.

Try this: push the N button before pushing the D button. Give it about 3 to 5 seconds between button pushes.

You asked about the conditions when to use D vs H. It kind of depends on your preference so a short explanation might help.

In H (or drive L), the trans is identical to older ultras as there is no shift at all. It starts & stays in high, and what you feel as a shift is the direct drive clutch locking out the torque converter. The acceleration is leisurely at best.

In 54, to compete with other mfg, the twin ultra was introduced which actually has a low to high shift and then to direct drive (D or drive R). Acceleration was acceptable and with more time, all the bugs would have been worked out.

Unfortunately, there were a lot of valve timing and linkage issues even into 56 so a heavy foot and mis-adjusted anything tends to shorten the life of bands & clutches as well as cause some weaker components to fail. So keeping that in mind, H is preferred, but if you let up on the gas at the shift points, stress on things will be greatly reduced and a satisfactory life to components can be expected.