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The ubiquitous automatic transmission is something that most of us take for granted in our daily routine, often leaving it negelected and misunderstood. Being complicated with many internal parts, it is one of the most expensive components to repair in our cars and trucks. This guide is for the daily user to get the most out of their automatic. It is not a “how to” tutorial on servicing and rebuilding transmissions nor does give a detailed explanation how an automatic transmission works. My goal is to dispel the many myths and otherwise bad information out there to help you, the consumer, make informed decisions when having your transmission serviced. And of course, this information should be useful anyone that services their own vehicle.

The first mass produced automatic transmission was GM’s Hydra-Matic introduced in 1939. With humble beginnings, automatic trasmissions have progessively gotten more and more sophistcated over the years. Throughout the 1950s, 2 speeds were the norm like in the Chevy Power-Glide. By then end of the 1960s, 3 speeds became the standard. A fourth, overdrive gear followed suit with electronic controls coming online in the 1980s. Now 5 and 6 speeds are common and there’s even an 8 speed available from Lexus! An automatic trasmission has hundreds of parts with some of these newer units having over 1,000 pieces which translate into more expense if they require replacement.

Automatic transmissions basically work with various internal components that are “held” and/or “applied” by friction devices known as clutches and bands. With the given combination of these applications, power is transmitted through the transmission at the necessary forward ratios or reverse.

The torque converter itself is a hydraulic coupling device that basically serves as a clutch between the engine and transmission. It is what allows your car to sit still at a redlight while in gear. Add engine speed and the converter hydraulically engages moving the car.

Automatic Transmission Fluid (ATF) is a hydraulic fluid that serves to clean, cool and lubricate the internal components of the transmission. It is the same fluid that creates the “coupling” in the torque converter. ATF is also what hydraulically applies the components mentioned above. The fluid distrubition is through the valve body, a device with a fine maze of small passages and valves. There are numerous gaskets, rubber o-rings and seals that keep the fluid where it belongs.

Knowing how this network of parts work is not as important as knowing these factors:

• There is pressure and friction going on inside of your transmission which means HEAT.
• There are small moving parts with close tolerances. They must remain CLEAN and move freely.
• Heat and contamination can damage and/or impede the operation of these components.
• The failure of a single component will cause a malfunction or complete failure of an automatic transmission.
• There is no such thing as a mechanic in a can.

Once something fails internally, it’s a diminished return; however there are some components that can be serviced without transmission removal or complete overhaul if they are dealt with promptly. Many times though, one failure will lead to another like dominoes.

Example: A small rubber seal loses its integrity because of excessive heat. This results in a loss of fluid pressure that would apply a component such as a clutch pack. That clutch pack begins to slip a little. The slippage generates even more heat damaging further components which causes even more heat. Friction media begins to shed itself into the “bloodstream” of the transmission. A particle of contamination impedes the function of another component and so on. It’s a vicious cycle of runaway temperatures until something finally burns itself out leaving you stranded.

Automatic Transmission Fluid is an often overworked and abused multi-tasker, as it cools, cleans, lubricates and is required to move parts under pressure. Over time, the heat and hard work will deteriorate the fluid and its ability to do the jobs we’ve asked it to do. It’s impotant for the fluid to be replaced at the manufacturer’s service intervals if not more frequently. This is especially important in heavy duty applications or severe operating conditions.

Something that is overlooked is the type of fluid that goes into your transmission. In the old days, it was pretty much Type F for Ford and Dexron for GM. Those days are gone and there are different types of fluid out there that are specifically engineered for the transmission they go in. Among other things, they each have different friction properties. They do not mix well and adding the wrong fluid type to your transmission can mean trouble down the road. Be wary of “universal” fluids. Your owners manual and sometimes dipstick will tell you what fluid goes into your transmission. I promise you that it will not say “Use only Universal Fluid from El Cheapo Auto Parts.” Some makes, especially German cars, specify a fluid that the chain parts houses do not carry. This means it will come from a dealer or import specialist and it’s expensive. It’s still better than replacing a $5,000 transmission though.

The fluid level and condition should be checked once a week. If you don’t know how to check your ATF, it’s pretty simple to learn. A mechanic should be glad to show you, especially if you’re a lady. The transmission should be completely warmed to operating temperature. The car should be on a flat, level surface and in P(ark) or N(eutral). With the warm engine running, pull the dipstick and wipe it clean with a lint free cloth or paper towel. Replace the dipstick making sure that it is fully seated. Pull the stick again and note its level in relation to the marks near the bottom of the stick. There are generally 2 marks around an inch apart. The warm fluid level should be up to the upper mark but not past it. A level showing between the marks is usually acceptable. If it is short of the lower mark, then the proper fluid should be added. This will require a funnel that will fit into the dipstick tube as it is added there. Only add a small amount at the time, checking the level frequently as you add. Do not over-fill your transmission. Different manufacturers will mark their dipsticks differently and often have some type of directions stamped onto the dipstick itself. Your owner’s manual or workshop manual should give you the information specific to your car.

This dipstick is from a 2002 Dodge Neon with about 150K miles and a fairly well maintained transmission. The fluid level is fine. The fluid condition is not bad but is dark enough to warrant a service in the near future. Notice that this stick has separate ranges for both “hot” and “cold.” The fluid still should be checked “hot” in which would be the upper 2 marks on this stick.

Along with the fluid level, it is important to pay attention to the condition of the fluid. A simple visual examination and smell test can tell you a lot about what is going on inside of your tranny.

Take a sniff of the fluid. It should smell like oil and nothing else. If it smells scorched, there is an internal problem. A friction component has gotten too hot and burned up. The scorched smell will coincide with very dark fluid color. Any particles on the stick, especially metallic, indicate an internal failure. If the car is still drivable with scorched fluid and/or a metal presentation, then it’s only matter of time before the transmission will die. Under those circumstances, servicing the transmission is a near moot point and may lead to a quicker break down.

Look at the color of the fluid after wiping some on a white lint-free cloth or paper towel. Fresh fluid will have a bright rosy color. It is normal for ATF to darken over its service life so don’t be alarmed if your fluid has a brownish tint to it. This is a good cue for a proper transmission service in the near future. If the fluid is really dark but not burned, the service needs to happen ASAP.

Heat is the number one enemy of automatic transmissions. Letting high temps take charge is asking for failure. Auto manufacturers build a small transmission cooler within the radiator which means it is being cooled by hot engine coolant. It is better than nothing but still short of ideal, especially when towing or someone with a hot foot. You will find that part of a towing package is an auxillary transmission cooler.

Adding an aftermarket cooler to supplement the factory setup is relatively inexpensive and good added insurance for your transmission. There are absolutely no downside to this with proper installation. Most do-it-yourselfers can do this at home in an afternoon or a reputable shop can install one for you. These kits can be purchsed for well under $100 with some starting under $50.

Touching on fluid again: Low fluid levels will cause temps to elevate and if it’s low enough, things will slip starting that vicious cycle I mentioned before. Adding a cooler will give a slight increase in fluid capacity which will can handle the heat better.

There is much debate, confusion and misinformation online regarding the proper service of automatic transmissions. A lot of well intended but misguided information comes from auto enthusiast forums. Many times information is quoted as fact but is actually someone regurgitating something they’ve seen before. There are extremely knowledgeable people online that provide great information but there are far more people that just don’t know. Before banking information, you should consider if the source has had formal training and professional experience etc. Cousin It may be handy with home repair, oil changes and tune ups but it doesn’t make him a transmission professional. Who’s to say he didn’t learn a bad practice from the World Wide Web…?

Automatic transmissions need to be properly serviced at their required intervals if not before. The debate is over how they are getting serviced.

•  Should the service be a drain and fill?
•  Should it be dropping the transmission pan, cleaning it and replacing the filter?
•  Should it be “flushed.”

These methods often get confused. There is actually more than one flushing method and a service doesn’t necessarily mean a flush was performed. The first is the “flush machine,” mostly found at the nation’s Fasty Lube chains. The other is a method used by dealerships, repair garages and the guys at home. Each have there merits and pitfalls.

There is one underlying fact that you should consider before making a decision on where or how you will get your transmission serviced. At the bottom of your transmission is a pan. Think of it as resovoir of sorts for your fluid. It is removable, and in most cases, it is removed to replaced the transmission filter. Over time, fine particles from normal wear accumulate in the bottom of the pan. Most pans will have magnets to keep the metallic particles in place. When you remove a pan you will have an almost paste like “slurry” coating on the bottom of the pan which consists of friction material and fine metal particles blended with fuid. Higher mileage, negelct and abuse will present more matter in the pan. Removing the pan is the only way to clean this gunk out. The pan pictured here is a fairly mild case with normal use and service.

The traditional automatic transmission service consisted of removing the pan, cleaning it and replacing the filter. Most pans do not have drain plugs so it can be messy. A drain plug is nice since you can drain the fluid then drop the pan. Some folks will tap the pan and add a drain plug for future service.

The downsides to this are: Not all of the fluid will be removed. The average car transmission will hold around 12 quarts of fluid, give or take. Trucks and SUVs will hold more. This method will only get 4-6 quarts however some cars have a drain for the torque coverter which may get another 4 or so quarts. Some consider this “invasive” and therefore risky.

The upsides are: You get that nasty gunk out of your pan. You get a new filter. The technician will get a good idea of the condition of the transmission based on what’s in the pan.

Some people elect to first clean the pan, change the filter then repeat changing the fluid until it has been mostly replaced. It’s easier with a drain plug of course.

One way of flushing the transmission is by disconnecting a cooler line from the radiator and pumping the fluid out (engine running) while adding new fluid through the dipstick.

The advantages are: All of the fluid can get replaced with less fluid wasted than in the traditional method. It is simpler, usually less messy and less invasive than the traditional method.

The disadvantages are: There’s a risk of pumping too much fluid out before replacing it with new fluid thus causing damage. This may not be so much an issue for professionals that use this method as it could be for a shadetree guy. The pan does not get cleaned or the filter replaced with this method alone.

The pan and filter may be serviced first and then the remaining fluid be flushed. I prefer this and this is how I service my cars as well as customers cars.

The 2nd flush method is via the hotly debated flush machine. These are mostly found at fasty lubes and muffler/brake/tire chains although a few shops and dealers are using them.

The advantages are: It’s fast and convenient. It replaces almost all of the fluid.

The disadvantages are: The obvious disadvantage is the pan and filter are not being serviced which in lies the problem of these machines. Some models of this machine use higher pressure to “power flush” the transmission. That alone may cause transmission damage. The bigger issue is that the abrasive sump slurry is being forced up into the filter and possibly into the delicate inner workings of the transmission.

Many people have had this procedure done and find themselves having their car towed into a transmission shop for a $2,000 repair bill. This doesn’t mean that using this machine will ruin your transmission but it has and may happen.

Defenders of these machines make these arguments:

• Replacing all of the fluid is better than a partial replacement. That in itself is true.
• Removing the pan is invasive and risky. False
• The filter is a simple screen and can be left in place. False. It is a very fine mesh that may become clogged when that past like slurry gets washed up into it. They were designed to be serviced and sold everywhere for a reason.

They also argue that newer model machines don’t use high pressure blah blah blah. It doesn’t matter. These machines do not clean the pan sediment from the transmission nor do they replace the fliter however they may very well wash it up into the old filter and beyond.

The machines are like slot machines. They are there to make Fasty Lube money. You may win or you may lose. In most cases, oil change technicians are not formally trained and certfied mechanics nor have they had training in automatics transmissions other than running the flush machine. I’m not attacking the individuals; they have a job to do and they do provide a convenient means of getting your oil changed, which everyone should be doing. The hook is they will invariably try to sell you overpriced products or services that at times are not even needed. Women are often easy targets of these services.

The youtube videos and before and after pictures are not telling the whole story. They don’t show what was in the pan and how it may have been washed through the transmission. Of course a freshly replaced fluid sample will be brighter than the old fluid. It will remain bright until a clogged filter or contamination stir-fries the transmission.

Defenders also say transmissions were ruined because they had a pre-existing problem. That may be true at times however a transmission on its last leg will tell you by the condition of the fluid. It’s not a good idea for a car owner to run get a flush when the transmission starts misbehaving. The average consumer may not know that though. They should actually have a mechanic check it first. A lube place with good practices should take a quick look at the fluid and ask the consumer questions before pushing another quickie flush sale and getting them out of the door.

I don’t know of any transmission shops that approve of these machines unless the pan and filter have been serviced first. Most transmission professionals will tell you to avoid them like the plague.

Finally, there is a newer type of flush machine known as a pump inlet flush machine. In this case the technician removes the pan for cleaning and replaces the filter. New fluid goes directly into the inlet and old fluid is removed without being recirculated through the transmission.

This advantage of this method is that it covers all of the bases: The mechanic can inspect the contents of the pan and clean it properly. You get all new fluid and a new filter. Its only disadvantage is the service will cost more which is insignificant compared to transmission repair.

I know that this was a lot of information but I hope that it will help you have the advantage in getting the most out of your automatic transmission. A happy transmssion makes for a happy car. A happy car makes for a happy car owner.

Shopping for tires is like shopping for a pair of shoes. You need something that fits right, that is going to perform well in whatever situation you are going to use them, and you want them to look good too! There are many different brand names out there, as well as many different places to buy them from. You can even shop for them online from the comfort of your own home. Shopping for tires isn’t hard, but it does require a little knowledge on your part to make sure that you get what you want.

Your vehicles tires are one of the most important parts of your car because they are the only part that actually comes into contact with the road. Because of this it is important to understand the basic functions of a tire and how to properly maintain them. The basic functions of a tire are:

1. To contain pressurized air – this is what actually acts as a barrier between the road and your vehicles wheels.
2. To provide a comfortable ride by absorbing impact from the road.
3. To transfer acceleration and braking forces to the road.

Before you can begin to shop around for the best deal on some new tires, there’s a few things you are going to need to know. The first thing is what kind of vehicle you have: year, make and model. Next is finding out what size tires your vehicle needs. To do this, you can go look on the sidewall of one of the tires that is currently on your vehicle now. The tire size will start with a “P” or “LT” and then a series of seven numbers. For example: P205/65R15. If you have a newer car and the tires on the car now were the original tires that came with it, they should be the correct size. If you are not sure if the tires on your vehicle now are the correct size, there are a few ways to find out: you can find this information either in your vehicles owners manual or on a tire information sticker inside the drivers door jam. If you don’t have an owners manual or can’t find the tire information sticker, you can: 1) Call your local tire store and have them look it up for you or 2) Look it up online through most major brand tire websites. Most of them have a tire size finder that you can use by typing in your vehicles year, make and model.

Your vehicles tire size may seem like a weird combination of letters and numbers that doesn’t really make any sense, but let’s break it down to better understand what each part means. Using the example of a tire size P235/75R15:

• “P” or “LT”? – “P” stands for passenger car and “LT” stands for light truck. Most vehicles, even SUV’s or small trucks still come with “P” designated tires. Usually, vehicles over 3/4 ton require the “LT” tires because these are heavy duty tires built with higher pressure ratings for heavy vehicles.
• “235” – The first three numbers of the tire size is the width of the tread measured in millimeters.
• “75” – The second two numbers of the tire size represent the aspect ratio, or tread to sidewall height ratio. Here, the tire sidewall is 75% of the tread width.
• “R” represents radial tire construction. Most new tires will have this designation.
• “15” – The last two numbers represent the tire rim size in inches. This tire size will only fit 15″ wheels.

You may also see a few more numbers and letters following your tire size. For example: P215/60R16 97H. These numbers represent your tires load rating and speed rating which you should make sure you look at when replacing your tires. If your vehicle gets installed with tires that do not have the recommended load and speed ratings for your vehicle, you can not expect to get good performance from your tires.

UTQG stands for uniform tire quality grading. These ratings were established by the national highway traffic safety administration and can help you in comparing tires. The UTQG rating will conist of a number and two or three letters. For example: 350AA.

• Treadwear – The first number is the treadwear rating. This is one of the best ways to compare tire mileage. The higher the number, the longer tread life the tires will have.
• Traction – The first letter is the traction rating. Tires traction ratings can be either C, B, A or AA with AA being the best.
• Temperature – The second letter is the temperature rating. “A” being the best B or C being next best.

When shopping for tires, use these grades as your basis for comparing tires. The most beneficial of these being the treadwear rating. You can compare and shop tires based on their mileage and comparing tire prices to mileage ratings. For example: a tire with a treadwear rating of 500 will last twice as long as one rated 250. If comparing two similar priced tires and one has a much higher treadwear rating, then you can expect to get higher mileage from the one with the higher treadwear rating at a similar price.

Buying tires from your local tire store can be convenient, but before you rush out the door, do a little research first. The best way to shop for tires from local tire shops is over the phone. Call around and check prices on your size tires and compare their brands. Get mileage ratings, performance ratings, and warranty information. Make a list of what brands they have, their mileage ratings and prices. Call around to a few local shops and compare what they all have. Another important point of comparison is their maintenance policy. Do they offer free tire rotation, balancing, and tire repairs? Does that come automatically with the tires or is it extra?

Online tire buying is a great new venue for tire shoppers. There are a few sites out there and they usually have pretty good deals. Sometimes these websites are even cheaper than the local tire shops. You can even have tires shipped directly to a local shop where you can have them installed! However, there are a few disadvantages to buying tires online. First is that sometimes you pay separately for tire mounting and balancing. This means that you buy the tires, have them shipped and then still have to pay someone else to install them on your vehicle. Another is that all warranties will be difficult to handle. If something were to go wrong with one of your tires and it needed replacement, you would have to have it shipped off to get it warrantied which could take weeks. Whereas with buying your tires through the local tire shop would have it replaced and back on your vehicle the same day.

While most whitewall tires are out of production, you can find a few companies out there who still manufacture them. If none of your local tire stores sell them in your size, you can try buying them online through Coker Tire.

Whether or not you should put them on your vehicle is entirely up to you. Whitewall tires look great on older vehicles, especially antique cars that originally came with them installed from the factory. However, it can look totally wrong on newer vehicles so take time to decide whether you think they would look acceptable on your car.

Most sports cars require special tires with specific speed capabilities. These are called high performance or ultra high performance (UHP) tires. These tires have a softer rubber compound which can flex and bend more than a standard passenger car tire can which helps with steering and braking at high speeds. If your vehicles manufacturer requires that you need high performance tires, you should absolutely buy them. Failure to keep your vehicle installed with high performance tires could cause you to lose control of your vehicle at high speeds. The big downside to having to buy UHP tires is that they are usually quite pricey, and because of the soft rubber compound, they normally do not get high mileage. Depending on their speed rating, most normally get between 10,000 to 40,000 miles before needing replacement so don’t expect to get out cheap on these tires.

So now that you know what tires are out there and compared prices, its time to decide which ones to get. Remember, though, that the most important factor in deciding which tires to get is to decide what works best for you. Do you not plan on keeping your car much longer? You may just go with the cheapest thing out there and not worry about mileage and warranties. Or you may think you are keeping your car for the foreseeable future and decide you want a long lasting, smooth riding set of tires. The choice is yours and it is entirely up to you how to go from here, so don’t let any smooth talking salesperson tell you what they think you should get. Remember, you being the customer, are always right!