Stepless Ratios in CVTs
Continuously variable transaxles use pulleys and a drive belt as the components needed to provide the vehicle with stepless gear ratios. The basic construction of a pulley is movable and stationary surfaces (see Figure 1). The drive belt Honda uses, constructed of about 280 elements held together by two 12-layer steel loops, is manufactured by Van Doorne Transmissie (VDT) of the Netherlands, with Honda giving it a little tweaking of its own (see Figure 2).
Close Counts Only in Horseshoes and Hand Grenades
Watch out when swapping stator shafts from one pump cover to another on 700-R4/4L60-E transmissions. We have all been there before. You have a unit with a good pump cover and a damaged stator shaft, and in your pile of parts there is a good stator shaft in a damaged pump cover. All you need to do is press the good stator shaft into the good pump cover and you will have what you need to get this car down the road today. Sounds simple, but how often are things that simple in this business?
Troubleshooting One-Way Clutches
There was a time when the only fact that you had to know about a one-way clutch was the direction in which the clutch freewheeled. Today you also must be able to troubleshoot some difficult problems related to one-way clutches.
What’s in Your Wallet?
For years now, almost everyone in the automotive-aftermarket repair business has been complaining that we did not have access to the same technical information that the car dealerships have. Well, now you do! But did you think it would be free?
Zap! It’s a MAF Sensor
When a MAF sensor malfunctions, it can do so in a very subtle way. It can create an erratic or incorrect signal on initial take-off, which can cause an elongated shift. It can deliver an incorrect signal at higher engine speed, which can create shudder that could be mistaken for torque-converter-clutch (TCC) problems. It can cause coast-downshift clunks, especially as the vehicle is coming to a stop. It can even cause a slide-bump shift. It is a major input for electronic pressure control that will result in elevated line pressure.
4L80 E Converter-Clutch Failure in 2000 & Up Vehicles
If you were involved in the transmission industry when the E4OD transmissions began coming to local shops, you probably experienced the nightmare of cracked converter clutches. The primitive code-retrieval methods on the early transmissions were usually little help in finding the root cause of the problem. The aftermarket converter rebuilders recognized the cracks in the converter clutches early on. Some made vain attempts at welding the cracked converter clutches, while most others recommended a factory replacement converter.
Gaining a Little Insight
A parallel hybrid vehicle allows the power from a gasoline engine and an electric motor to drive the vehicle independently or in conjunction with one another. The Toyota Prius has such a design as well as the Honda Insight and the Civic Hybrid. Although they are all parallel hybrids, there are differing operational strategies between Toyota and Honda.
Fix in a Flash
Occasionally, we find the problem to lie outside the transmission/transaxle, in such parts as the MLPS (manual-lever position sensor), TPS (throttle-position sensor) or MAP (manifold-air-pressure) sensor, to name a few. Though it’s rare, even the computers/modules (such as the vehicle control module (VCM), transmission control module (TCM), powertrain control module (PCM) or engine control module (ECM)) fail from time to time. We have become accustomed to troubleshooting these systems, and although they are becoming somewhat routine, we all know that we run into some problems that “push” you. They either push you into being a better technician or push you closer to finding a different occupation.
To Flash or Not to Flash
At this point, everyone is familiar with the fact that most 1996 and later GM vehicles are equipped with computers that must be programmed (flashed) in order for the vehicle to operate properly.
What some technicians may not be familiar with is the fact that earlier GM vehicles were equipped with PCMs that are also flashable. As a matter of fact, you could have a GM vehicle as early as the 1993 model year that is equipped with a flashable PCM. This is mostly because GM was the pioneer in developing the EEPROM and the programmable process.
The Toyota Prius P111 Hybrid Transaxle
The Toyota Prius P111 hybrid transaxle shown in Figure 1 is a continuously variable transaxle. If you are already familiar with a Subaru Legacy or a Honda Civic HX, you might think this is another CVT with a belt and pulleys. Not this unit…
4L60-E: 4×4 Low Range Only After Overhaul
Once you are aware that the wire harnesses can be connected incorrectly, it is easy to look back at the problem. When the transfer-case motor-encoder plug is connected to the oxygen sensor, it will short, blowing the fuse; and when the oxygen-sensor plug is connected to the motor-encoder, it shifts the transfer case to 4×4 low range..
