Packard Forum Index » V-8 (1955-56)

My February of 1955 TU has 65,000 original miles. It's never been rebuilt. I know the answer to this question is completely subjective and dependent on so many things, but...how much longer does it likely have before it takes a dump and leaves me stranded way out in BFE?

I fully serviced it with a complete drain and refill of Type F (getting the bell housing off to drain the converter SUCKS!!!), adjusted the bands, adjusted the selector linkage, and adjusted the throttle linkage. There was more metallic gray sludge in the pan than I am used to seeing on 1970's automatics, but maybe that is normal for TU's, and I do not know the last time it was changed.

It shifts perfectly. No flare or hang-up between low and high and it's smooth. The converter lockup to direct drive happens very smoothly. There is no "groan" or "moo", just a smooth slide into direct drive. I actually wish it was less of a slide and more of a firm shift to save wear on the clutch. I've developed the habit of lifting off the throttle at around 30 mph to make it lock quickly and not under load to save wear.

I moved the adjusting link on the throttle rod rearwards about 3/8" to make the transmission think the throttle way farther open. I thought this would raise the shift points and firm them up, reducing wear on the transmission. It's a trick the Mopar guys use on Torque Flites. It did raise and firm-up the shifts at first, but then one day it suddenly got really bad flare between shifts and slipping in all drive ranges. It scared the living daylights out of me. I thought my transmission was dying. Talk about being white as a ghost! Fortunately, I was barely outside my driveway. I adjusted the linkage back to factory setting and it's been 100% fine ever since. I don't know why it would do that. It goes against logic. Maybe the selector was between ranges or the governor stuck. I don't know, but I sure as heck am never doing that again! That was scary as #^@$$.

Anyway, so...do Twin Ultramatics usually make it to 100,000 miles before needing rebuilt?

Thanks.

I have owned a 1955 Packard 400 since 2003. The best ultramatic that car ever had was the one it came from the factory it lasted 51 years until it blew up on the Pennsylvania turnpike. After that it was like a game of musical chairs with rebuilt ultramatics (3) none of which lasted more than 2 years. If some day your Ultramatic goes to that great auto salvage yard in the sky, here is what I suggest get a conversion kit from Bendtsens and a rebuilt 700r General Motors transmission. The cost for the conversion was about $3500 but from a reliability performance and gas mileage standpoint it was well worth it. My car now had more pickup and way better gas mileage that it ever had with Ultramatic.

What mileage was that at?

Deleted post.


The mod is for 56. Not for a 55

The mechanical components are quite robust and the clutches adequate for normal use.

I've built oh, maybe a hundred of them over the last 30 years and here is what I observe.

Many of them die by driver assisted suicide. I just had in two in a row where the throttle pressure was so far off they were killing themselves by excess slipping on each shift and the drivers had noticed--nothing. Once upon a very long time ago the dealer might have noticed during routine service and made the 3 minute correction. No one since.

Others die by overheating; thin, hot fluid wont pump up to proper pressure reducing the holding power of the clutches. That is why I bore large holes in the bell housing to aid in cooling the convertor as that is where most heat is created. An air cooler in place of the water cooler (overheated engine leads to overheated trans) is not a bad idea either.

Occasionally I see units where there might have been an alignment issue between engine and trans causing wear on the shafts where they pass through the bushings. That leads to low pressures and sloppy shifts.

There are also a variety of annoying secondary mechanical issues such as overtravel of the parking pawl and the detents flying apart. But these are usually not killers.

Many of the problems I see are caused by appalling workmanship and neglect. The dealers weren't there to take care of the cars as they aged.

My old 56 Super shifted exactly the same after 40K miles as it did the day I built it. When properly adjusted I find them fun to drive as they are very responsive to what the driver's foot tells them to. This is very nice on winding country roads.

Ross, what should one be noticing to catch those common problems?

Probably well over 250,000 miles yeah for real.

Hello Ross, I have had a number of Ultramatic Packards and pulled out and overhauled the Ultra and Twins probably at least 10 times over the past 50 years. I have a 56 Patrician with 55k miles. I recoed the trans of my 56 Patrician with new bushes, seals throughout and It appears to be going ok now but I was advised to fit a power steering filter into the cooling pipe circuit to catch all of the dregs which you find in the sump. I have fitted it and noticed that the Direct Drive engagement "bump" is not as strong. I fear that Direct Drive pressure may be suffering due to excessive converter back pressure caused by the filter. Any advice would be appreciated.

Good question William. Engine runaway on the low-high shift--even a little bit-- is a no-no and a sign that the throttle pressure is set a bit too low, or that the low band is adjusted a tad too loose. If that "flare" can not be adjusted out the high range clutches or the bushings and seals that operate them are suspect.

A soft or groaning direct engagement is often a sign that the direct clutch has gotten hard and glazed or that the pressure supply is failing, usually due to worn bushings.

Peter, a small increase in residual pressure in the convertor will oppose the direct clutch. I suppose as long as you are not getting slipping your filter is OK.

On the trans I build I always modify the valve bodies for higher shift points so the trans in not in the middle of the brisk acceleration period when it makes its l-h shift (Usually in the middle of the intersection). I find the factory setting quite annoying in that regard. Then direct comes in at the period of lightest accel and I usually lift my foot slightly to bring it in when I wish.

As much as we may grumble about Ultramatics please keep in mind that the competition had their troubles too. Hydramatics were reliable and efficient but the shift characteristics of the early ones were so annoying I can't bring myself to buy a car afflicted with one.

Thanks Ross. While we're talking transmissions, when I put my 400 in R after starting it, the transmission will stall out the engine unless I rev it up significantly. However once it's past that and in R it idles fine, shifts to D fine, basically is fine the rest of the drive.

In the troubleshooting section, looks like it might be Condition 15, "Chatter when starting in reverse" and it suggests adjusting the reverse brake band. How much of a problem would it be to keep driving the car like this? Obviously I can start backing it into my driveway so I can start it in Drive and hopefully avoid this problem. I won't be able to drop the transmission on this anytime soon.

On Hydramatics:
It's true the Hydramatics had their own annoyances. The most significant in comparison to the Ultras is that the Hydras had only a fluid coupling, not a torque converter. For this reason, they needed to have 4 speeds (3.82, 2.63, 1.45, direct) to provide sufficient torque. Whereas the TC in the Ultras needed only a 1.82 low gear, optional at that. So whereas the Cadillac owners manuals could brag about having the most used automatic in the world, in getting up to cruising speed you'd feel 3 gearshifts each time, compared to only 1 or 2 in the Ultra (including the feel of the TC locking up).

5540:
Yeah if it was over 1/4 million miles I'm not concerned then. I doubt even my 2010 Traverse will make it that far without major service.