Packard Forum Index » V-8 (1955-56)

got a twin ultramatic that neutrals when it goes into direct drive.

Assume it is a 55? Was it a sudden failure or has it been coming on or has the car been sitting a long time and this is the symptom you found after getting it started and driving again.

If the gear select indicator is on the arrow to the right of D and using light to normal throttle does it do the low-high shift OK at approx 15 or so and then when time for the high-direct transition is when it fails? When you say it "neutrals" does that mean the engine just races and there is absolutely no forward gear or does the high range stay selected and it will still go but it sounds like the engine is racing and the clutch is slipping. If you let off the gas does it try to go back in normal high range operation or does the trans stay in "neutral"

G'day garydub55,
to PackardInfo!

I invite you to include your 55(?) Packard in the Packard Owner's Registry.

hrpms until you let up then shifts backinto gear .pressure guage never shows any rise in pressure. converter would air check on bench.

The manual on-line here lists a valving problem and a torque converter valve problem.

There was also a TSB for "runaway shift" between lo and high which called for deletion of an accumulator spring.

As well there are after market springs to improve Lo-Hi shift quality.

However, the first step is to check the throttle valve linkage. I found that even a slight misadjustment can prevent direct drive engagement. So download all the service literature and TSB's for Ultramatic. There is a revision for the throttle valve linkage adjustment in the TSB's as well.

I would start by working within the Left D quadrant (Torque convert start or High Range) to address the lockout clutch problem.

That fact that it does engage indicates an adjustment or valving issue.

It sounds as if a valve is sticking or a pressure is wrong. To go into direct drive requires a balance of pressures. Throttle pressure is controlled via the linkage and then farther regulated by a couple of valves. The result is sent to one side of the direct drive valve where it is combined with spring pressure against that side of the valve. That pressure needs to be correct and one of the regulating valves could be sticking. If too high the DD valve can't move. The governor sends a pressure to the direct drive valve piston which is on the other side of the valve. When the governor pressure exceeds the regulated throttle and spring pressures the direct drive valve moves to apply pressure to the DD clutch piston and engage the clutch.

If the other L-H shift is OK chances are the governor and throttle valve is functioning but I think I would check governor pressure to rule it out. If that is OK then the direct drive piston operated by governor pressure or the DD valve itself being stuck is suspect.

You mention doing some checks with air pressure. By any chance was the valve body taken apart during a rebuild or cleaning? If so, the torque on bolts reattaching the bodies to the manifold is important. Packard issued bulletins on erratic operation or sticking valves caused by improper torque on the bolts twisting and binding the valve bodies. The chart and torque is on page 50 of the gear start training manual or the Twin Ultramatic section of 55-6 Service Manual. You can download either from the literature section. If valve body hasn't been apart there could be a chunk of some foreign material binding the valve.

Another significant issue has been worn bushings or damaged areas of the input shaft where the bushing cannot contain the pressure. If the pressure is lost the DD piston doesn't have enough strength to clamp the clutch disc.

Hi all,
I also have a noise when the car drive slowly and the transmission goes to high range (but only when I accelerate hardly) ... don't know where (clush ?)

It's a 1956 Four hundred with 56.000 miles

If you could describe the noise and also define what you are calling high range we might be able to come up with some better ideas.

If you have the selector on D and mean the first shift into high (the only actual shift the transmission makes) then noise at that moment is something I don't recall anyone mentioning. You have a band loosening and clutches applying almost simultaneously. If timing is not perfect and things did not move in the right order it could result in both being applied at once and some bogging and maybe noise. The usual complaint at that shift which Packard called "flare" was low released quickly and high was slow coming in so it would almost be like the car was in neutral for a moment. The engine would speed up which you would hear and then have to slow down abruptly as the high range clutches took the load. That results in a rough jerking shift and a lot of heat and wear on the high range clutches.

If you have selected H (or are in D after it shifts into high) and you mean it is happening at the final transition as it goes into direct drive then a noise is sometimes heard if the direct drive clutch plate lining has hardened or glazed over. It has been described as a groan or a cow like mooing sound which goes away once the clutch is fully engaged or if you let off the gas while the transition is taking place. If that is the noise, most just live with it and help keep it silent by letting off the gas for a moment while the clutch applies.

G'day Emmanuel,
to PackardInfo and for including your very nice looking '56 Four Hundred Hardtop Coupe in the Packard Owner's Registry, not many members from Belgium! Sorry to hear of your trans problem.

Take heart, there are more than a few of us with 1956 Ultramatics that have dried out direct drive clutches that will "grumble" right after that upshift if the accelerator isn't slightly relaxed as the direct drive clutch engages. After a couple of years, lifting my right toe just a bit has become second nature to me. It's a small price to pay for not removing and opening up the transmission for a quality rebuild.

For those of us old enough to remember riding GM diesel buses in the 1950s, this "lift the toe to shift up" activity is almost nostalgic. As a kid I asked a bus driver if it was necessary and was told that it was. I believe that their Allison transmissions had only two speeds and was just as slushy as any Dynaflow, PowerGlide or Ultramatic (1950-1953, before Gear-Start). But they were durable and endured millions of miles of the toughest city bus routes and drivers. When the previous owner-mechanic told me how to do it in a Packard, it was deja vu all over again.