Great stuff Joe keep it up

Videos

• The CAR WIZARD talks transmissions
  "Take it to a specialist"

Conventional Automatic Transmission

(this section does not apply to other types of transmissions)

Checking your Automatic Transmission Fluid (ATF)

There are many different automatic transmissions. Some have dipsticks, and some do not. Read your owner's manual for the proper checking procedure. Check it periodically to make sure your transmission has enough fluid, and that it isn't worn out. (every oil change for example)

Pictured: ATF on the dipsitck and blotted on paper

Sample taken in clear container (you can see through it when new):

Maintenance

The fluid

All ATF wears out eventually. Changing the fluid is essential to keep your transmission shifting properly for a long time. Older cars needed fluid changes approximately every 30,000 miles. Today, with improved synthetic fluids, and cooler running transmissions, the fluid can last longer. 60,0000 miles or more. Consult your manual to verify your change interval (unless it says "lifetime". There is no such thing). When the fluid turns brown, has particles in it, or smells burnt, you should replace it.

In most circumstances, removing the cover, draining out the old fluid, and refilling with new is all that is required. A service shop may offer you a transmission "flush". There are various methods, but usually the mechanic connects a machine to the transmission fluid cooling hoses to capture old fluid, and put new fluid in. If you service your transmission regularly, and on time, then a flush is usually unnecessary.  If done improperly, flushing can lead to problems, and sometimes even failure. Unfortunately, some modern vehicle transmissions were not built with removable covers. They are assembled permanently. On these, replacing the fluid through the ports or cooler lines with an exchange machine is the only option.

If your transmission is already worn out and the fluid has never been changed, then replacing the fluid can cause it to slip more severely, and shift poorly or not at all in some cases.

Signs that your transmission is near the end of its useful life:

• It "slips" (vehicle does not accelerate when you press the accelerator)
• It begins to shift too late, there is hesitation, the shift duration is long, or it slams into gear.
• Fluid shows black particulate contamination (clutch material has been used up)

This usually happens when the transmission reaches around 200k miles (varies by model and service history of course). If your transmission does not have advanced mileage ( <150k miles ), the fluid looks fairly clean, and it has not exhibited any of the above symptoms, then you should continue to service it. Neglecting to maintain a healthy transmission (or any machine) will guarantee that it will fail sooner. If you are uncertain, then service the transmission, but pour the fluid that you drain out in a clean container, and keep it on your shelf.

If your transmission starts to show any symptoms, stop driving it immediately and tow to a transmission expert for diagnosis. Continuing to drive with a faulty transmission, even a few miles, can add hundreds or thousands of dollars onto the repair bill.

The filter

If your automatic transmission has a removable cover, then it likely has a replaceable filter. The filter is designed to trap material suspended in the fluid that damages the transmission. Over time the filter fills up, and eventually it could block the flow of the fluid, causing poor shifting performance or worse, starve the transmission of fluid, and destroy it. Always change this inexpensive filter when the fluid is changed. Also change the filter seals and cover gaskets that come with the filter kit, making sure to remove all traces of the old ones. They can be difficult to see, and leaving them in there can lead to fluid issues.

Some transmissions have an internal metal mesh screen which is not serviceable without removing the entire transmission unit. These transmissions are designed for fluid exchange only.

A dirty filter:

Additives

There are products on the market sold as transmission additives. They make various claims about restoring function to aging transmissions, such as restoring seals, improve or stabilize fluid properties, restore shifting etc. If your transmission is shifting poorly, then it may already be worn out. Adding these products can not fix a worn transmission. But it might restore some shifting performance for a short time. It is not advisable to dump in a whole bottle. Add it little by little, until function returns. More is not better.  These products can be used as a stop-gap measure, or as a last resort. For example, you may need a car to run for a few more months until you get rid of it.

You should never put additives in a healthy transmission. They should not be used as a "preventive" measure. The fluid already contains everything the transmission needs. Do not use additives to "prolong" the life of the fluid. When it's due, just replace it. Unnecessary use of additives can reduce the life of your transmission.

Continuously Variable Transmission (CVT)