Re: Help with purchase selection

Posted by HH56 On 2016/1/26 23:22:56

The regular Ultramatics made thru mid 54 are good reliable units as long as it has had decent service and you drive with a little decorum. If it has been serviced by a good mechanic I wouldn't hesitate to drive one cross country. The transmission is unique so It takes a bit of getting used to because they are essentially a single speed non shifting transmission. The car starts and stays in either high or low range depending on your gear selection. There is one transition from converter drive to direct drive in either gear which happens at a speed anywhere from approx 20 to maybe 40 depending on throttle. That is not an actual shift but rather a clutch plate coming in to lock the converter into a single unit. The direct drive will drop out and go back into converter for increased acceleration when you floor the accelerator if the car is below approx 50. If over that speed it stays in direct drive. When coming to a stop direct drive will drop out at approx 11mph so the engine won't stall.

The biggest issue in driving comes when the operator manually changes gears, particularly if he chooses to shift into low for a faster takeoff from a stop. Once the car is moving he wants to shift into high range again. Problem with that action is the trans wasn't designed for that operation so there is no timing in the trans between low range band release and high range clutch application. If one lags and one comes in early the engine will bog way down because both gears are selected or if the opposite happens it could run unloaded because neither gear is engaged. With the latter situation If engine suddenly has to slow down because a gear finally engages a considerable amount of stress is generated in the transmission. If you are going to drive with low to high manual shifts, by all means let off on the gas while the change is made and don't accelerate again until the shift has completed. Trying to keep up with the Porsche club or being the first to the next stoplight is definitely discouraged.

Packard realized the shifting problem and tried to help the situation by making an improved timing kit available in 54. That helped but did not solve the entire problem. The 53 could possibly have the kit installed but still it is best to use restraint. The issue was finally addressed with the late 54 gear start which had a selection for the automatic low to high shift and on to direct drive. Unfortunately there were some teething problems so the Ultras started getting a reputation. That was only worsened when essentially the same straight 8 gear start transmission was placed behind the high horsepower V8 engine in 55. By the time 56 rolled around and almost all the problems had been addressed, it was too late.

Service can be a big item. The transmission is constructed quite differently than most automatics and very few mechanics understand them or will take the time to do things properly -- if they even agree to look at one. There are only a few mechanics around today that can really work on them with any hope of a true factory or dealer quality job . Improper service, failure to replace worn parts -- particularly bushings and even the main shaft -- during a rebuild or improper adjustment -- particularly in the throttle linkage -- can make things go down hill in a hurry. The fluid path moves thru rotating shafts and relies on tight bushings around the shaft to maintain pressures. Any wear that results in pressure loss and things start to slip and overheat. Pressures also depend on the throttle linkage. More throttle and higher pressure is called for and that is determined by the adjustment.