We'll cover all these topics and more below.What is a Transmission Solenoid?A transmission solenoid is an electro-mechanical component "valve" used to control the flow of transmission fluid in the transmission.  A typical automatic transmission uses a number of different solenoids for different purposes.  The opening and closing of the solenoids is controlled electronically by the vehicle's Engine Control Module (ECM) or Transmission Control Module (TCM), depending on the vehicle.A modern-day transmission uses solenoids to engage and shift gears, called shift solenoids, which are normally mounted to the transmission valve body.  There is also a Transmission Pressure Control Solenoid and a Torque Converter Clutch Solenoid.What Exactly Do Transmission Solenoids Do?The best way to explain what transmission solenoids do is to describe the different solenoids that are used in an automatic transmission.  The following describes the different solenoids along with their functions.  Also included are problem symptoms, repair information, parts and estimated repair costs.

F  No Downshift(s):Erratic Shifts: Once it is determined that you have a failed transmission shift solenoid the only repair is to replace the faulty part.  Replacing a transmission shift solenoid can be done by most any auto repair shop, automobile dealership service center or you can do-it-yourself "DIY".Run Lse T ShirtReplacing a transmission shift solenoid or a shift solenoid pack involves dropping the transmission oil pan in order to access the valve body, (where the solenoids/solenoid pack is mounted), locating and replacing the faulty solenoid and then replacing the oil pan using a new pan gasket before refilling the transmission with the correct automatic transmission fluid (ATF).Rent Travel Trailer Bakersfield CaNOTE: On some vehicles, the transmission solenoids are part of a solenoid pack.  Zillow Homes For Sale Tonawanda Ny

In these instances, you must replace the solenoid pack.Shift Solenoid: REPLACEMENT COST The cost for transmission solenoid replacement depends heavily on the type of vehicle you drive.  For example, a single transmission shift solenoid can cost anywhere from $15 to $100.  A solenoid pack, which includes all the solenoids for a particular vehicle/transmission can cost from $65 to several hundred dollars or more.  Where you get the work done, (whether at a local auto repair shop, car dealership or you do-it-yourself), also factors heavily into the cost of repair.  If you replace the solenoid yourself, the parts supplier you purchase the solenoid (or solenoid pack) from will factor into your final cost.Below are transmission solenoid replacement costs for four different vehicles.  Use this information to give you a rough idea of what your cost might be.  Transmission Shift Solenoid Replacement Cost   2004 TOYOTA SIENNA :   : 2000 FORD FOCUS    2008 BMW 330i :   : 2003 CHEVROLET SUBURBAN      $12.49 & Free Shipping        **      Xs4z7h148aa Focus Automatic Transmission Shift Solenoid$31.00 & Free Shipping        **Transmission Shift Solenoids - All Vehicle Makes and ModelsGuaranteed Quality - Guaranteed Low Prices    Diagnosing a failed transmission solenoid with Check Engine LightA failed transmission solenoid will normally set a diagnostic trouble code (DTC)

, which will cause the check engine light to illuminate.  In these instances, an OBD-II scan of your vehicle's computer will provide information pointing to the faulty solenoid.  The DTC information (or explanation) will almost always include a statement indicating that the problem may be an open circuit in the transmission electrical system.  Therefore, you should always test the solenoid to verify its condition before replacing it.Diagnosing any Transmission Problem with NO Check Engine LightA correct diagnoses of a transmission problem when there is no check engine light is best accomplished with a professional transmission scan.  This type of scan will necessitate a visit to a transmission shop or car dealership.  A professional transmission scan can cost between $60 and $125.  This charge is normally referred to as a diagnostics fee.  It is standard procedure for the shop making the repair to waive the diagnostics fee. )A failed transmission solenoid or an open circuit anywhere in the electrical system may cause the transmission to go into Fail Safe (or "limp" mode as it is also called) in order to protect the transmission from internal damage that might be caused by the faulty solenoid or open circuit. 

In fail safe/limp mode, the transmission will have limited functionality and will lock in either 2nd. When the transmission is in fail safe mode, the vehicle should only be drive home or to the repair shop.  Maximum speed while in limp mode is around 30 mph.Continuing to drive the vehicle with the transmission in fail safe or driving faster than the recommended fail safe speed will cause the transmission to overheat.  Excessive heat build up in an automatic transmission is the #1 cause of catastrophic failure.  So, avoid extended driving when the transmission is in fail safe mode.Transmission Torque Converter Clutch Solenoid    Shift Solenoids for as low as Find your best price here. Does a timing chain (as opposed to timing belt) need any specific maintenance? In particular I'm talking about a BMW Z4 While regular maintenance is not required it is advisable to check how much the chain has stretch, say every few 100K. If the chain stretches too much the tensioner may no longer be able to perform its job.

There's also the problem of the pins becoming a bit loose in the side plates. The chain should also get a visual check whenever the opportunity presents itself to ensure there is no evidence of things like side plates starting to become loose. Rollers should be felt to ensure there is no discernible ply between roller and pin. Timing chains don't often break but when they do they generally take chunks of engine with them, as well as allowing valves to get too friendly with the pistons on most engines. I'm used to timing chains on American V8's, but they will "stretch" over time (think 200k miles) and sometimes on high mileage engines they could "jump" a tooth if they are too stretched out. But they do not require any maintenance. Regular maintenance is not needed. However, a "rattling" noise that changes with engine RPM may indicate a problem with the chain or timing gears. Usually this isn't an issue until higher mileage (150k +). Next time you go by your dealership, ask them if they've had any problems in particular with your year model.

If you hear of instances of chains commonly being replaced at X miles because of some problem (and you trust your source), then you may want to take preemptive action. BMW timing chains are engineered for the life of the engine and never need maintenance or replaced. To prove that point BMW has always performed several long distance tests on its new engines before they are put on the market. Back in the 90s they took a e34 (5 series) and ran it over 2 million miles, just performing the standard maintenance. When they took apart that engine everything measured to spec. Enjoy your Bimmer and just make sure to get the regular maintenance performed but no need to worry about the timing chain. Now if your a e30 guy like myself your stuck with the single worst decision, sorry second worst (hiring Chris Bangle), Bimmer engineers made and that was to go with a 'quieter' rubber band timing belt. long chains will get loose sooner, hard shifting will knock it around and shorten its life, infrequent oil changes will interfere with lubrication as the carbon biulds up on the chain.