Question:

Where is the transmission dipstick on a 2002 Ford Explorer?

There is no transmission dipstick. In order to service the trans fluid level, you have to raise the vehicle, and the vehicle MORE?

A dipstick is one of several measurement devices. Some dipsticks are dipped into a liquid to perform a chemical test or to provide a measure of quantity of the liquid. Since the late 20th century, a flatness/levelness measuring device trademarked "Dipstick" has been used to produce concrete and pavement surface profiles and to help establish profile measurement standards in the concrete floor and paving industries. A testing dipstick is usually made of paper or cardboard and is impregnated with reagents that indicate some feature of the liquid by changing color. In medicine, dipsticks can be used to test for a variety of liquids for the presence of a given substance, known as an analyte. For example, urine dipsticks are used to test urine samples for haemoglobin, nitrite (produced by bacteria in a urinary tract infection), protein, Nitrocellulose, glucose and occasionally urobilinogen or ketones. They are usually brightly coloured, and extremely rough to touch. Dipsticks can also be used to measure the quantity of liquid in an otherwise inaccessible space, by inserting and removing the stick and then checking the extent of it covered by the liquid. The most familiar example is the oil level dipstick found on most internal combustion engines. Other kinds of dipsticks are used to measure everything from fuel levels to the amount of beer left in an ale cask (Firkin). "Dipstick" is the trade name of a profiling device manufactured by Face Construction Technologies of Norfolk, Virginia USA. The instrument is used in 63 countries on six continents to measure the flatness and levelness of concrete floor slabs and pavements. The Dipstick measures concrete floor slab flatness/levelness in terms of Face Floor Profile Numbers ("F-Numbers"), a profile measurement system adopted in 1990 by the American Concrete Institute. F-Number measurement procedures were established by ASTM Standard E1155. The instrument also measures TR-34 Free Movement (FM); TR-34 Defined Movement (DM); Gap under Sliding Unleveled Straightedge; Gap under Rolling Straightedge; and DIN 18202. The U.S. Federal Highway Administration (FHWA) and the World Bank (with its International Roughness Index... or "IRI") have established measurement procedures using Dipstick profiler data. The American Association of State Highway and Transportation Officials (AASHTO) has established its Standard R 41 (most recently published as R 41-05 (2010)) to, "... manually collect precision profile data utilizing the Face Technologies Dipstick. The dipstick measures profiles (relative elevation differences) at a rate and accuracy greater than traditional rod and level surveys. Procedures for measuring both longitudinal and transverse profiles are described." The Dipstick, with a reported accuracy of .01 mm ( 0.0004 inches), is also the most widely used and accepted Class 1 profiler for the purposes of calibrating other profilers. Dipstick was used to obtain data that were used as ground truth in FHWA evaluations of the repeatability of IRI values as measured by other profilers and in Long-Term Pavement Performance (LTTP) studies conducted by several states. The instrument was similarly used to produce reference measurements by the World Road Association (PIARC) in its 1998 "International Experiment to Harmonise Longitudinal and Transverse Profile Measurement and Reporting Procedures." The PIARC experiment was conducted in the USA, Japan, Holland and Germany and included IRI values from airport runways and super highways to rough unpaved roads. The word "dipstick" is also sometimes used as a slang term to refer to either the penis or, more commonly, a stupid person.][
In modern usage, a torque converter is generally a type of fluid coupling (but also being able to multiply torque) that is used to transfer rotating power from a prime mover, such as an internal combustion engine or electric motor, to a rotating driven load. The torque converter normally takes the place of a mechanical clutch in a vehicle with an automatic transmission, allowing the load to be separated from the power source. It is usually located between the engine's flexplate and the transmission. The key characteristic of a torque converter is its ability to multiply torque when there is a substantial difference between input and output rotational speed, thus providing the equivalent of a reduction gear. Some of these devices are also equipped with a temporary locking mechanism which rigidly binds the engine to the transmission when their speeds are nearly equal, to avoid slippage and a resulting loss of efficiency. By far the most common form of torque converter in automobile transmissions is the device described here. However, in the 1920s there was also the pendulum-based Constantinesco torque converter. There are also mechanical designs for continuously variable transmissions and these also have the ability to multiply torque, e.g. the Variomatic with expanding pulleys and a belt drive. A fluid coupling is a two element drive that is incapable of multiplying torque, while a torque converter has at least one extra element—the stator—which alters the drive's characteristics during periods of high slippage, producing an increase in output torque. In a torque converter there are at least three rotating elements: the impeller, which is mechanically driven by the prime mover; the turbine, which drives the load; and the stator, which is interposed between the impeller and turbine so that it can alter oil flow returning from the turbine to the impeller. The classic torque converter design dictates that the stator be prevented from rotating under any condition, hence the term stator. In practice, however, the stator is mounted on an overrunning clutch, which prevents the stator from counter-rotating with respect to the prime mover but allows forward rotation. Modifications to the basic three element design have been periodically incorporated, especially in applications where higher than normal torque multiplication is required. Most commonly, these have taken the form of multiple turbines and stators, each set being designed to produce differing amounts of torque multiplication. For example, the Buick Dynaflow automatic transmission was a non-shifting design and, under normal conditions, relied solely upon the converter to multiply torque. The Dynaflow used a five element converter to produce the wide range of torque multiplication needed to propel a heavy vehicle. Although not strictly a part of classic torque converter design, many automotive converters include a lock-up clutch to improve cruising power transmission efficiency and reduce heat. The application of the clutch locks the turbine to the impeller, causing all power transmission to be mechanical, thus eliminating losses associated with fluid drive. A torque converter has three stages of operation: The key to the torque converter's ability to multiply torque lies in the stator. In the classic fluid coupling design, periods of high slippage cause the fluid flow returning from the turbine to the impeller to oppose the direction of impeller rotation, leading to a significant loss of efficiency and the generation of considerable waste heat. Under the same condition in a torque converter, the returning fluid will be redirected by the stator so that it aids the rotation of the impeller, instead of impeding it. The result is that much of the energy in the returning fluid is recovered and added to the energy being applied to the impeller by the prime mover. This action causes a substantial increase in the mass of fluid being directed to the turbine, producing an increase in output torque. Since the returning fluid is initially traveling in a direction opposite to impeller rotation, the stator will likewise attempt to counter-rotate as it forces the fluid to change direction, an effect that is prevented by the one-way stator clutch. Unlike the radially straight blades used in a plain fluid coupling, a torque converter's turbine and stator use angled and curved blades. The blade shape of the stator is what alters the path of the fluid, forcing it to coincide with the impeller rotation. The matching curve of the turbine blades helps to correctly direct the returning fluid to the stator so the latter can do its job. The shape of the blades is important as minor variations can result in significant changes to the converter's performance. During the stall and acceleration phases, in which torque multiplication occurs, the stator remains stationary due to the action of its one-way clutch. However, as the torque converter approaches the coupling phase, the energy and volume of the fluid returning from the turbine will gradually decrease, causing pressure on the stator to likewise decrease. Once in the coupling phase, the returning fluid will reverse direction and now rotate in the direction of the impeller and turbine, an effect which will attempt to forward-rotate the stator. At this point, the stator clutch will release and the impeller, turbine and stator will all (more or less) turn as a unit. Unavoidably, some of the fluid's kinetic energy will be lost due to friction and turbulence, causing the converter to generate waste heat (dissipated in many applications by water cooling). This effect, often referred to as pumping loss, will be most pronounced at or near stall conditions. In modern designs, the blade geometry minimizes oil velocity at low impeller speeds, which allows the turbine to be stalled for long periods with little danger of overheating. A torque converter cannot achieve 100 percent coupling efficiency. The classic three element torque converter has an efficiency curve that resembles ∩: zero efficiency at stall, generally increasing efficiency during the acceleration phase and low efficiency in the coupling phase. The loss of efficiency as the converter enters the coupling phase is a result of the turbulence and fluid flow interference generated by the stator, and as previously mentioned, is commonly overcome by mounting the stator on a one-way clutch. Even with the benefit of the one-way stator clutch, a converter cannot achieve the same level of efficiency in the coupling phase as an equivalently sized fluid coupling. Some loss is due to the presence of the stator (even though rotating as part of the assembly), as it always generates some power-absorbing turbulence. Most of the loss, however, is caused by the curved and angled turbine blades, which do not absorb kinetic energy from the fluid mass as well as radially straight blades. Since the turbine blade geometry is a crucial factor in the converter's ability to multiply torque, trade-offs between torque multiplication and coupling efficiency are inevitable. In automotive applications, where steady improvements in fuel economy have been mandated by market forces and government edict, the nearly universal use of a lock-up clutch has helped to eliminate the converter from the efficiency equation during cruising operation. The maximum amount of torque multiplication produced by a converter is highly dependent on the size and geometry of the turbine and stator blades, and is generated only when the converter is at or near the stall phase of operation. Typical stall torque multiplication ratios range from 1.8:1 to 2.5:1 for most automotive applications (although multi-element designs as used in the Buick Dynaflow and Chevrolet Turboglide could produce more). Specialized converters designed for industrial, rail, or heavy marine power transmission systems are capable of as much as 5.0:1 multiplication. Generally speaking, there is a trade-off between maximum torque multiplication and efficiency—high stall ratio converters tend to be relatively inefficient below the coupling speed, whereas low stall ratio converters tend to provide less possible torque multiplication. While torque multiplication increases the torque delivered to the turbine output shaft, it also increases the slippage within the converter, raising the temperature of the fluid and reducing overall efficiency. For this reason, the characteristics of the torque converter must be carefully matched to the torque curve of the power source and the intended application. Changing the blade geometry of the stator and/or turbine will change the torque-stall characteristics, as well as the overall efficiency of the unit. For example, drag racing automatic transmissions often use converters modified to produce high stall speeds to improve off-the-line torque, and to get into the power band of the engine more quickly. Highway vehicles generally use lower stall torque converters to limit heat production, and provide a more firm feeling to the vehicle's characteristics. A design feature once found in some General Motors automatic transmissions was the variable-pitch stator, in which the blades' angle of attack could be varied in response to changes in engine speed and load. The effect of this was to vary the amount of torque multiplication produced by the converter. At the normal angle of attack, the stator caused the converter to produce a moderate amount of multiplication but with a higher level of efficiency. If the driver abruptly opened the throttle, a valve would switch the stator pitch to a different angle of attack, increasing torque multiplication at the expense of efficiency. Some torque converters use multiple stators and/or multiple turbines to provide a wider range of torque multiplication. Such multiple-element converters are more common in industrial environments than in automotive transmissions, but automotive applications such as Buick's Triple Turbine Dynaflow and Chevrolet's Turboglide also existed. The Buick Dyna flow utilized the torque-multiplying characteristics of its planetary gear set in conjunction with the torque converter for low gear and bypassed the first turbine, using only the second turbine as vehicle speed increased. The unavoidable trade-off with this arrangement was low efficiency and eventually these transmissions were discontinued in favor of the more efficient three speed units with a conventional three element torque converter. As described above, impelling losses within the torque converter reduce efficiency and generate waste heat. In modern automotive applications, this problem is commonly avoided by use of a lock-up clutch that physically links the impeller and turbine, effectively changing the converter into a purely mechanical coupling. The result is no slippage, and virtually no power loss. The first automotive application of the lock-up principle was Packard's Ultramatic transmission, introduced in 1949, which locked up the converter at cruising speeds, unlocking when the throttle was floored for quick acceleration or as the vehicle slowed down. This feature was also present in some Borg-Warner transmissions produced during the 1950s. It fell out of favor in subsequent years due to its extra complexity and cost. In the late 1970s lock-up clutches started to reappear in response to demands for improved fuel economy, and are now nearly universal in automotive applications. As with a basic fluid coupling the theoretical torque capacity of a converter is proportional to $r\,N^2D^5$, where $r$ is the mass density of the fluid (kg/m³), $N$ is the impeller speed (rpm), and $D$ is the diameter(m). In practice, the maximum torque capacity is limited by the mechanical characteristics of the materials used in the converter's components, as well as the ability of the converter to dissipate heat (often through water cooling). As an aid to strength, reliability and economy of production, most automotive converter housings are of welded construction. Industrial units are usually assembled with bolted housings, a design feature that eases the process of inspection and repair, but adds to the cost of producing the converter. In high performance, racing and heavy duty commercial converters, the pump and turbine may be further strengthened by a process called furnace brazing, in which molten brass is drawn into seams and joints to produce a stronger bond between the blades, hubs and annular ring(s). Because the furnace brazing process creates a small radius at the point where a blade meets with a hub or annular ring, a theoretical decrease in turbulence will occur, resulting in a corresponding increase in efficiency. Overloading a converter can result in several failure modes, some of them potentially dangerous in nature: