There are a number of different fluids employed in every Pontiac. These can be classified as working fluids like that in the hydraulic braking system, or lubricating fluids such as engine oil, or a combination of both. In an automatic transmission, the fluid is both a worker and a lubricant, since hydraulic pressure and flow are part of the fundamental design of a self-shifting gearbox.

It needs to be recognized that no fluid (working or lubricating) has an unlimited service life. The chemistry of these fluids is very complex, and over time the components wear out, become diluted with moisture through absorption, and are contaminated by the surfaces they contact. Numerous heat cycles on a vehicle that is used year-round takes its toll on the fluid’s ability to perform its designed task.

Pontiac deemed service with the proper fluid is a sure way of maintaining your vehicle, but through spectrum analysis of the used fluid, a wealth of information can be gleaned. Think of it as a blood test for a Pontiac. Fluid analysis allows you to confirm the condition of the component, the track wear, and catch a problem before it becomes a major issue. Best of all, fluid analysis is a cost-effective means to not only build a history on your Pontiac, but it can be considered a forensic investigation of an engine or component that you are considering buying.

A small sample sent to a test laboratory will tell you the true story about the component -- the only caveat being that the fluid must have seen some use before testing for it to be accurate. If the seller changed the fluid and did not run the engine or car long enough, it is akin to checking the fluid right from the bottle.

The best method to obtain a sample is through an application-specific extraction pump, as seen in this story ($45). This is non-invasive and allows in-service samples to be checked without violating the system in question. If you are checking the fluid on your own Pontiac -- for example, the engine oil -- it can be done when it is being changed. Simply follow your normal drain procedure, letting the oil run from the pan for a few seconds so that the dirt from the drain plug is not captured, and fill the clean bottle supplied by the test lab. Seal it up and send it out.

Each test lab will provide application- specific instructions for its service, but generally they are not too different from what is represented here. Engine oil, transmission fluid in either a manual or automatic gearbox, and differential lubricant are the most common areas to check. Some labs like to check the power-steering fluid also, but it is less common.

The actual method to analyze a fluid for foreign material and overall condition is quite complex and employs many different sciences. For this article, HPP worked with On-Site Analysis (OSA) in Sandy, Utah. The company produces a line of accurate analytical equipment and also offers fluid testing as a service to the public. Tests are conducted using infrared spectroscopy and emissions to monitor engine and transmission wear, as well as the physical properties of the fluid and its condition.

OSA tests for nine elements -- six wear metals and three contaminant metals, along with other areas. An analysis costs $14.95 and checks 30 different areas. A complete report is provided that includes the amount of contaminants or material found, a glossary of terms, and the corrective action/response required.

HPP will now provide a little background on the history and types of fluids found in a Pontiac to further establish the value of analysis.

Fluid Dynamics

Engine Oil

Engine oil is a common area to analyze and testing can reveal much, especially if you are worried about using newer formulations in an older Pontiac. (We have covered the properties and rating systems for engine oil at length in two previous stories, “The Slippery Truth About Motor Oil” and “Juggling the Truth About Today’s Oil,” both of which can be referenced on, so we won’t delve into those areas in this story.)

For example, if potassium is discovered in the oil, it can be an indication of coolant migration. Silicon is the most common cause of wear, and indicates the presence of dirt or seal material. Other metals identify a problem in the valvetrain or rotating assembly.

Transmission Fluid

The first automatic transmission to resemble what we know today was introduced by General Motors in 1937 as the Oldsmobile Safety Transmission. It employed a simple fluid coupling and semiautomatic gear changing. This was superseded in 1939 by the first fully automatic transmission, the Oldsmobile Hydramatic, using planetary geartrains and manual, and hydraulic controls for the clutches and bands.

Following problems with the earlier units after a recommendation for the use of engine oil as the working fluid, GM Research, which worked closely with Mobil, designed a fluid with better low-temperature characteristics for the new transmission. Buick pioneered the replacement of the simple fluid coupling (which offers no torque multiplication) with a torque converter type in its 1948 Dynaflow, which resulted in a transmission very similar to what our readers are familiar with today.

With the introduction of the torque converter, more heat was generated in the transmission, and an improved type of fluid was required. In 1949, GM issued its Type-A specification for a fluid, which was succeeded by Type A Suffix A in 1957. These were initially the standard specifications for transmission fluids, but Ford in 1960 and Chrysler in 1964 issued their own specifications, while GM again introduced an improved fluid know as Dextron in 1967.

Due to the internal clearances and choice of friction-materials employed by the Detroit manufacturers, in most cases the automatic-transmission fluid is brand-specific. Using the wrong fluid in a transmission can result in poor performance, improper shift characteristics, leaks, and complete failure.

All automatic-transmission fluids share basic requirements. To overcome the heating and churning action within the transmission casing, oxidation-inhibited and non-foaming oil is essential. To maintain cleanliness within the gearbox, a dispersant is added, and a viscosity modifier prevents excessive thinning of the fluid when it becomes hot.

The fluid must also be compatible with the seals of the transmission and not corrode any of the metallic components. It should also guard against internal corrosion from atmospheric moisture when left standing.

Not only must the fluid not attack the friction surfaces, but it must also provide the correct frictional characteristics as the clutches and bands come into engagement. These required frictional characteristics are specified by the transmission manufacturers and must not change significantly over the life of the fluid. They are evaluated in bench clutch-pack friction tests and in “shift feel” testing on the road.

Through the late ’70s, there was a major difference between the frictional requirements of Ford and those of General Motors and most other manufacturers. Today there are only minor differences between the GM Dextron II, Dextron III, and the latest fluids for GM vehicles.

Make sure the fluid you purchase can be retrofitted to the older transmission in your Pontiac. All major brands of automatic-transmission fluids will list the retrofit capability of their product so it can be used with no worry. Read the label!