FAQs

How do I check automatic transmission fluid level? How much it will cost to repair a transmission leak? Am I safe driving with a transmission leak? How much will a transmission overhaul/rebuild cost? How long does an automatic transmission normally last? How can I make my automatic transmission last longer? Okay, I have a transmission problem. What options are available? Trouble with a computer controlled transmission. What now? What does "scanning" a transmission do? What's the difference between soft parts and hard parts? General information regarding computer controlled transmissions     How do I check automatic transmission fluid level? Check fluid level with the engine running (except Honda), the transmission in "Park" (except Chrysler products which should be in neutral with the emergency brake applied), and with the engine at operating temperature. Remove the dipstick and wipe clean. Fully insert the stick and remove. Check both sides of the stick to determine correct reading. Repeat the process. The reason you have to check both sides of the dipstick is that circulating fluid can have surface waves. This creates an uneven level and some fluid will "slosh" onto the stick and give a false reading. Some transmissions are worse than others. Note: If checking the fluid level immediately after the engine has been off for a long time, fluid from the torque converter will drain back into the pan area where the level is measured and give you a false high reading. When the engine is started, the fluid in the pan area is used to fully charge the transmission and torque converter. Also, a difference in fluid temperature will affect the measurement. Fluid volume expands when heated to operating temperature. Tip: If you have added fluid, go through the same procedure, but allow the engine to run for a few minutes and repeat the process several times before determining what is the accurate reading. Some of the added fluid will adhere for a while to the side of the filler tube and give a false reading until it all settles into the transmission. Tip: If the fluid level is low, you have a leak! Transmissions do not consume fluid. Have the leak diagnosed and repaired to prevent more serious problems. After you have added fluid, drive the vehicle for a mile or two, then recheck the level. This is especially important in front wheel drive vehicles. -------------- How much it will cost to repair a transmission leak? There are numerous places from which a transmission can leak. They include: the pump, shift lever seal/s, kickdown seal, electrical connection/s, governor cover, speedometer, rear output seal or axle seals, servo cover/s, filler tube, throttle cable, pan, side cover, cooler lines, and differential cover. The real question is: What is the source, or sources of the leak. Most people can only see the bottom of the unit, and therefore conclude that the bottom pan gasket is leaking when, in reality, the leak is from above and running down and around the pan. Therefore, it is imperative that the unit be visually inspected to evaluate the leak situation! So, to answer the question is, unfortunately, not possible without at least a visual inspection. -------------- Am I safe driving with a transmission leak? It depends on the rate of fluid loss. A minor or slow leak will allow you to drive as long as you maintain the level in the normal range. You will have to establish the rate of loss and replenish as necessary. It should be obvious that if fluid is running out as a stream, that you won't go very far. A transmission will usually operate normally until the fluid loss is a quart or more. Then the unit will exhibit abnormal operating symptoms and internal damage is occurring. What started as only a leak can result in a major repair bill if ignored! --------------- How much will a transmission overhaul/rebuild cost? What model are we talking about and how do you know the transmission needs to be overhauled? Occasionally, a poorly running engine, broken motor mounts, restricted exhaust, electronic or electrical, or other problem not internal to the transmission will be the cause of abnormal operation. Proper diagnosis is the only way to determine what needs to be done and at what cost. --------------- How long does an automatic transmission normally last? There is no accurate answer. The mileage or time of use before major problems occur will vary greatly, and therefore, I don't dare suggest a specific expectation. It is true that most modern transmissions, barring damage from poor maintenance, overheating, or other abuse, tend to work properly for something more than 100,000 miles. The three major factors in transmission life expectancy are periodic maintenance, maintaining proper fluid level, and moderate driving habits. --------------- How can I make my automatic transmission last longer? Maintenance! Check the fluid level periodically, repair any leaks/problems promptly, service the unit on a regular basis, and add an auxiliary cooler if the vehicle is used for towing, commercial, or high ambient temperature climates. Units subjected to heavy towing or performance driving conditions should have a shift kit installed. Synthetic fluid may benefit some applications by lowering operating temperature resulting in a longer life, but not all transmissions can use synthetic fluid. Check with your local ATRA shop for their advice to your specific application and needs. --------------- Okay, I have a transmission problem. What options are available? Diagnosis comes first! Find out the cause and extent of the problem. The symptom may be caused by electronic controls or external mechanical influences (broken motor mounts, CV axle problems, etc.). Once we know that your problem is internal in the transmission, Diablo Transmissions offers options you cannot find at other shops. Some transmission shops shy away from doing individual repairs and lean heavily toward rebuilding only. Repairs are often the best way to go. If the situation warrants, a simple repair can, in certain situations, solve your problem and regain all your remaining usage. At other times, an in-shop rebuild will not be a sufficient answer. In these cases we offer factory remanufactured transmission at very attractive prices. As the only local distributor of "Certified Remanufactured Transmissions" we provide you with the utmost in quality at true wholesale prices. --------------- Trouble with a computer controlled transmission. What now? If you notice problems with your transmission's operation, don't automatically assume that the problem is actually in the transmission. Computers receive information from numerous sensors, process the information, and then signal/operate the transmission. Often, the problem is in one of the sensors, an electrical connection, or system ground. In such a case, work on the transmission will not resolve the problem. Scanners can "read" the codes stored in the computer and help pinpoint the source of most problems. --------------- What does "scanning" a transmission do? Scanning involves attaching a small diagnostic computer to a terminal in your vehicle. This device is then used to address your computer to determine if any trouble codes are present and to "read" the output from numerous electrical sensors that feed information to the computer. All of this information is useful in determining the integrity of the electrical control system for the transmission. Scanning is an essential part of the diagnostic process. Note: Expect a nominal charge for this service. Also note: When the computer "sees" any parameter from various sensors that does not fit established criteria, the computer will set a code for each error. However, there are some errors that will be present that the computer will not sense because they are within the normal range but are not necessarily valid. In that case, the system has to be diagnosed to determine if applicable sensors or other electrical components are performing incorrectly and creating an abnormal transmission operational response. ---------------- What's the difference between soft parts and hard parts? Soft parts include clutches, bands, overhaul kit, filter, internal sealing rings, bushings, external seals and gaskets. These are the parts, along with a torque converter, that are always replaced during an overhaul of a transmission. Upon internal inspection, some major component parts may also need to be replaced such as the pump, a clutch drum, or a planetary gear set. There's no way to know the condition of these "hard parts" before the unit is disassembled in order to include them in an estimate. In the "old days" the cost of these parts was minimal due to the limited variety of transmissions and could be included in the estimate, however late model, computer controlled units can have very expensive parts that may need to be replace to insure that the unit is fully repaired. Therefore, it is common for a transmission shop to include a list of commonly replaced parts, and allow for possible surprises until after an internal inspection of the unit can be made. --------------- General information regarding computer controlled transmissions: Late model transmissions are controlled by a computer that operates shift and pressure control solenoids inside the transmission. Therefore the computer needs to be electrically scanned by a repair professional to determine if any electronic control problems exist. When the computer sees a signal, from any of the various sensors, that does not fit established criteria, the computer will set a code for each error, which will be evident by a "check engine" and/or a flashing overdrive light. However, there are some errors that will be present that the computer will not sense because they are within the normal range. In that case, the system has to be diagnosed to determine if applicable sensors or other electrical components are performing incorrectly and creating an abnormal transmission operational response. The following sensors are usually part of the transmission: MPLS (Manual Linkage Position Sensor), input and output speed sensors, shift solenoids, governor sensor, etc. Please be aware that some sensors are not part of the transmission itself, but in other areas of the vehicle. These include the TPS (Throttle Position Sensor), the MAS (Mass Airflow Sensor), MAP (Manifold Absolute Pressure sensor), PCM (Power Control Module or Computer), DSS (Differential Speed Sensor), CTS (Coolant Temperature Sensor), IAT (Intake Air Temperature), etc. Also, be aware that a scan done at a "parts store" will not show all of the information necessary to form a conclusion about an electrical control problem. A lot of problems in the control system do not set a code in the computer, but can still cause transmission problems. When the shifts of a computer controlled transmission are excessively firm, the pressure regulator may set to maximum pressure by the computer if it senses a problem from one or more sensors. The results of this diagnostic testing should indicate whether the problems are in the control system, the transmission, or both. When the ignition key is cycled, the computer is reset and will control the transmission normally until an error is registered. Then the transmission will be placed in "limp" mode (2nd gear) again. I've found that it is much better to evaluate the situation "hands-on" than to speculate over the phone. Over the years, I've been amazed at the number of times the conclusion made before seeing a vehicle changes after it is inspected and the situation is diagnosed.