Powerglide

The Powerglide is a two-speed

History

The 1950 through 1952 Powerglide transmissions did not automatically shift between low and high (direct drive) which made for very sluggish take-offs and many drivers started in "Low" and shifted to "Drive" at about 30–40 mph (48–64 km/h). The 1953 and later units when in "Drive" started in low and automatically up shifted to high at a speed determined by the throttle opening. By the mid-1950s, more than half of all new Chevrolets were sold with Powerglide.

In 1962, GM started building Air Cooled Powerglides in

The Powerglide continued to serve as Chevrolet's main automatic transmission through the 1960s, when a new three-speed automatic transmission called

Usually, Powerglides were coupled with the

Two primary types or versions of the Powerglide were made. The "Cast Iron Powerglide" transmission introduced in 1950 featured a cast iron case; after 1963, the "Aluminium Powerglide" substituted aluminum versions of the case and several other parts. Early models were air cooled, and later 60's versions used a fluid cooler in the radiator. The Aluminium Powerglide, and Tempestorque was used from 1962 until it was replaced with the Turbo-Hydramatic series of transmission in 1973. The Aluminium Powerglide is still used today as a racing transmission of choice by many racers mainly for the fact that it only shifts once, and for its extreme durability. It is also possible to purchase all the parts needed to build an Aluminium Powerglide from scratch from most racing parts vendors.

Torque-Drive

For the 1968 model year, Chevrolet introduced a semi-automatic version of Powerglide marketed under the name Torque-Drive. This unit was basically Powerglide without the vacuum modulator, requiring the driver to manually shift gears between Low and High. The quadrant indicator on Torque-Drive cars was, Park-R-N-Hi-1st. The driver would start the car in "1st," then move the lever to "Hi" when desired.

Torque-Drive was only offered on low-horsepower engines for

Identification

General Motors transmissions have markings to identify;

• Casting numbers on the case and extension housing.
• Powerglide transmissions were cast with the word Powerglide along the body
• Date Casting Codes
• Assembly Date Code Stamping - can be stamped anywhere...
• Chassis VIN Number stamping or "source serial number"- beginning in 1962

Prior to 1967, transmission ID numbers contained the plant prefix code, month and date of production (expressed numerically) and a shift code (D = Day, N = Night). From 1967 on, the ID number contained the transmission type or plant prefix, Date (coded below) and a shift code. The constants in decoding the trans ID number are the date the transmission was produced.

• Pre-67 Example: C213N - (C = Cleveland Powerglide, February 13, Night Shift)
• Post-67 Example: P9E03 - (P = TYPE, 9 = year (1969), E = Month, 03 = Day of Month)

The transmission identification number or source serial number (chassis VIN) is usually located close to the transmission code. This number will contain a division identification number, the model year, and the assembly plant and production sequence (last 6 digits) of the vehicle identification number (VIN) stamped onto the transmission.

• Example: 19N500001^[4]

Safety issues

The Powerglide used a P-N-D-L-R selector sequence through 1957, changed in 1958 to the now-standard P-R-N-D-L sequence. The earlier sequence had been criticized on safety grounds for placing reverse after a forward gear, instead of having neutral between reverse and the forward ranges. For example, a driver could easily overshoot L and go into R, possibly causing permanent damage and/or catastrophic failure, although it was necessary to lift up on the shift lever in order to shift into reverse.

Turboglide

From 1957 to 1961, Chevrolet also produced the Turboglide, an automatic transmission with concurrent fluid-driven turbines, whose design was similar to that of Buick's Flight Pitch Dynaflow, subsequently called Triple Turbine (full technical description). The Turboglide, only offered with V8 engines, was more expensive (by about $50) than the Powerglide and did not have wide acceptance, in part due to failures in 1957-58 models, which were addressed by a significantly upgraded version for 1959.

Corvair Powerglide

Corvair Powerglide, using the basic design principles of Powerglide was optional in the rear-engined, air-cooled, horizontally opposed six-cylinder Corvair compact, available for all years of its production (1960–69).

Swapping

Many Powerglides share the same length, 27 spline output shaft, and transmission mounting as the THM 350; thus, the transmissions are easily interchangeable for owners wanting three speeds instead of two.^[5] Other Powerglides came with an incompatible 16 spline output shaft.^[6]

Racing

Although it is a very old design, the Powerglide still has a strong following in drag racing due to its strength and simplicity.^[7] Powerglides are also popular in mud racing and monster truck racing. In the first few years after introduction, they became known as the "Slip-N-Slide Powerglide", due to the fluid coupling, as opposed to the mechanical coupling of a clutch-driven gearbox, and the "Positive-Pop transmission". This last is due to the characteristic "bump" or "pop" which occurs as the transmission is put into gear from neutral.

Currently Robert Campisi from Australia holds the World Record for the fastest run using a Powerglide transmission, clocking 5.95s at 260 mph in his Twin Turbo Ford Mustang in September 2011.^[8]

See also

• List of GM transmissions
• Turboglide
• Turbo-Hydramatic
• Corvair Powerglide

References