History of Auto Trans

buick

#1

Reading a story recently in which a 1949 Buick (no model specified)played a part. The driver “flipped the shift lever to park.” Did a 1949 Buick have “Park” as a shift lever option, or was ‘Park’ a later development?


#2

http://files.conceptcarz.com/img/Buick/49_Buick-Roadmaster-DV-10-RMA_i010.jpg

'49 Roadmaster shifter column.

And in other news, I want that car.


#3

Thanx, conceptcarz.com for that fast response and the clear foto of the 49 Buick shift lever! G.


#4

The automatic transmission in the Buick did have a “Park” position. This transmission was introduced in 1948 in Buick’s Roadmaster series and called “Dynaflow”. In 1949, this transmission was available in the Roadmaster and Super series, but not int the Special. General Motors Hydramatic automatic transmisison which was first offered in the 1940 Oldsmobile, the offered in the Cadillac a year later, and then the Pontiac in 1948 did not have a “Park” position. GM made Hydramatics were installed in Lincolns beginnng in 1949, Nash in 1950, and Hudson, Kaiser, and Frazer in 1951. There was no “Park” position in any of these cars. The Chevrolet automatic transmission, called PowerGlide was introduced in 1950 and did have a “Park” position. The FordoMatic and MercoMatic transmsissions for the Ford and Mercury that came out in 1951 did have a “Park” position. The Chrysler Powerflyte which became available late in the 1953 model year for the Chryslers and was available for all Chrysler products in 1954 did not have a “Park” position.


#5

The reverse gear with an early Hydramatic was the “Park” gear. I learned to drive with an early Pontiac with a Hydramatic which had four forward speeds. Buick Dynaflows had a single speed and were sluggish. I often wonder why GM used the Hydramatic on Cadillacs, Oldsmobiles and Pontiacs but not Buicks, one level below Cadillac in the GM quality level. It might be possible that Hydramatics would shift roughly between second and third gear unless fairly frequent adjustments were done at the dealer. The Dynaflow, however slow, would not need these adjustments.


#6

Actually thre were 2 speeds in the Buick Dynaflow, but you had to start it “Low” range. In “Drive” you depended completely on torque multiplication from the torque converter. The GM hydramatic did not have a torque converter, but had a fluid coupling between the engine and the transmission, so there was no torque multiplication.
The Chevrolet Powerglide was much like the Buick. However, in 1953, the Powerglide was modified to start off in low and shift to direct drive when the selector was placed in “Drive”.

I read somewhere that the GM Hydramatic would jerk too much in the Buick and Chevrolet since these cars had a closed driveshaft (torque tube drive), while the Pontiac, Oldsmobile and Cadillac had an open driveshaft (Hotchkiss drive). However, the Nash had the torque tube drive and used the GM hydramatic. I rode in a 1950 Nash with Hydramatic and didn’t notice that it jerked severely when shifting form gear to gear.

By the way, when the GM Hydramatic plant had a fire in 1953, some 1953 Pontiacs were supplied with the Chevrolet Powerglide and some Oldsmobiles may have had the Buick Dynaflow.


#7

The reverse gear with an early Hydramatic was the “Park” gear. I learned to drive with an early Pontiac with a Hydramatic which had four forward speeds.

I remember these old Pontiacs very well. 1948 wsa the first year that Pontiac offered the Hydramatic automatic transmission. There was no neutral switch. The starter in in all Pontiacs was activated by a floor pedal right above the accelerator. When you stepped down on the pedal, it pushed the starter pinion into the flywheel, depressed the accelerator a bit, and closed the starter switch. On the Hydramatic equipped models, there was a system of levers that raised the selector into neutral. Neutral was at the top of the shift quadrant and reverse was at the bottom. You parked the car in reverse and when you went to start the car, stepping on the starter pedal moved the selector lever up to neutral. In 1949, the starter for the Pontiacs was a pushbutton on the dashboard and there was a neutral safety switch.


#8

Thanx to both shadowfax and Triedaq. You both were a big help. Geoff